... make a lemon hat for your cat.
Fly Molo here with a pep-talk to get your through your next game.

There's an old Standard Bearer article in an old White Dwarf that has imprinted itself on my memory. It was about the "face." You know the face you get when your dice can only roll 1's and you start picking up models by the handfuls. The face you get when your best laid plans appear to be lined up to deliver you an advantage when you completely whiff against all odds.

"The Face" is the manifestation of your disappointment with your game. With fate. With everything related to your Warhammer experience at this current moment. It is a hostile one. One that is not amused by humor or other positive happenings. One that is not enamored with your opponent's paint job. It is a face that lets your opponent know that they aren't your friend for the next few hours.
And no one wants to play a game with someone who doesn't want to be their friend.
But this isn't about that article. If you want to read that one, go dig up your White Dwarf collection and read it. But it is pertinent, hence, why I brought it up.
I hope that this article will strike a chord with everyone who has ever shot a Bolter, including you beardy WAAC players AND you soft and cuddly fluff bunnies AND you beer and pretzels target demographic players.

Starting Off Bad
You're playing your Drop Pod Marines from your homebrew Space Donkeys Chapter. You try to land you first pod, full of Tactical Squad Jackass, onto an objective right in your opponents deployment zone. Sadly, you scatter an unlikely 11 inches straight towards the table edge and land with a fin off of the board. Mishap time. You toss the fateful die and up comes a "1." Shucks. Tactical Squad Jackass has met an untimely end.
Ah well. You, being a stubborn ass, decide to land your second pod, full of Tactical Squad HeeHaw, next to the objective, ready to claim in where Jackass had failed. You decide to land in the same spot, considering its nearly perfect and rolling 11 or 12 straight back is very unlikely. Alas, an 11 is rolled in the exact same direction. That same fracking fin is hanging off of the edge and you enter mishap city again. And that fateful mishap die rolls up another "1."
ARE YOU FU#$ING KIDDING ME!?
Boom, you're in somewhere near a 375 point hole, before a shot has even been fired. Twenty Marines are waiting to have their geneseed collected by a lucky Apothecary, if they can be recovered from the flaming wreckage from the drop pods. Your opponent's objective isn't contested. And you're pissed. And you opponent is smug and happy.

Starting off bad is probably the most common cause of rage-quits, even above rules disputes. People rage quit from bad starts in Magic all of the time, even in pretty competitive events. Even if a rage quit doesn't occur, the person is usually so rattled by their anger that they are nowhere near 100% on their game. That matters if winning matters. And let's face it, winning matters. We wouldn't play a game that is me vs. you if winning didn't matter.
So what can we do here? We see that going into the tank when things start off badly has a negative effect on our outcome, and not just because we lost models unluckily. It is because we're mentally out of it. We tend to focus on the negative. The 'woe-is-me' syndrome.
So, let's not do that. Simple, right?
Right and wrong. Right is the sense that's all we need to do. Wrong in the sense that its easier said than done.

"Your mind is a garden, your thoughts are the seeds. You can grow flowers or you can grow weeds."

We can choose what to think. We can choose how to think. We can choose not to go into the tank and we can choose not to feel like shit when things don't go our way. We control ourselves. We aren't children anymore.

Another way you can logic your way into a better position is by changing the narrative. Change the game. Think: "Can I win a 2000 point game if I only bring 1625 points? I do believe I can. It will be hard, but of course I can do it." And you can. Andre Agassi would crush me in a game of tennis if he was using a Walmart racket and I had the top-of-the-line super T10200XL eXtreme racket that cost me $2200. He possesses the skills to pay the proverbial bills. He will still win one handed. You can win your Warhammer game, it's just going to be harder.

And there's other advantages to be noticed here. When you have terrible luck and seemingly go into the tank, your opponent is (hopefully secretly) licking his lips. He is just rubbing his hands together, imagining how great it will be to notch up maximum battle points and move on to the next round. He might be so confident of victory, that he starts to play a little loose. You need to take advantage of that and play ultra-tight. If there is any hope of winning, you need to keep playing. And there is ALWAYS a chance of winning if you have a model on the table. You just need a chip and a chair.
If winning seems a lot less likely, what is needed to get maximum battle points? What is needed to get a draw? Start playing a different game. Your opponent is probably going to switch gears into 'I'm-going-to-try-and-table-this-guy,' you should probably switch gears into the 'while-my-opponent-tries-to-table-me-I'll-try-to-win-the-objectives' or something similar.

Not the competitive type but just want to have a better time after a really unlucky start? Change the narrative! Whoops! 'The Drop Pod Assault of Rast VI' just became the 'Miracle of the Great Donkey on Rast VI,' where after a catastrophic ambush on the first landing Pods, the Space Donkeys stayed gritty and turned a certain defeat into a glorious victory for the Emperor! Your counts-as-Lysander Commander Stan Burro, smote foe after foe with his Thunder Hammer Donkey Punch, against all of the odds. Your troops channeled the fury of the Great Donkey to win one for the Emperor. Or the battle just became the 'Massacre of the Equidae Host,' where your chapter experienced a formative moment in it's history, ala the Crimson Fists. Either way, it should make your game a lot funner. Er, a lot more fun. Funner. I have saved myself in a not-so-competitive game with my brother recently in this way, after losing my Monolith to a deep strike mishap and having a 20-man warrior blob and Overlord get run down in combat. The game looked grim, but after changing the narrative a little, my Necrons managed to come back from the edge of phase-out and snatched a victory from the vile Chaos Marines.

Snatching Victory Out of the Jaws of Defeat
Bad luck or unfortunate events can occur later in a game and often do. At this point, you're heavily invested into the game, mentally and chronologically. And Lady Luck decides to pop a squat right over your Cheerios.
Your Daemon Prince whiffs his nine warp-speeded iron-armed WS9 attacks on the charge, causing only three hits, all of which failed to wound that one-wound Riptide, then he throws back his single Smash attack, which hits on a 5, wounds on a 2+ and you fail your 5+ that rerolls 1's. You had nine chances to kill that fracker and statistically should have caused 2.6666 unsaved wounds with your conservative strength 7. He should only instant gib you less than 19% of the time when he gets his single attack back. That scenario has probably played out quite a few times considering two of the top armies regularly use Daemon Princes or Riptides.
Considering the points costs of those two models, this moment in the game is probably huge. Its obviously past turn 1, considering it involves an assault on a weakened Riptide. So from here, the Prince either wins as expected, and moves on to other juicy targets behind the Tau lines... or the other scenario occurs, the Prince is smashed and the Riptide goes on to put a gaping hole into one of Fateweaver's heads, and the game is going in a very different direction for the Deamons player.
How can we handle this? How do we roll with the punches when those punches hurt so bad? Again, its about perspective. The game went from being a competitive game to a nearly assured defeat. Nearly is the key. Reassess the situation. See what you have left. See what your opponent has. How has the board changed? Who is in control of the objectives? Keeping your head cool and understand that swings in luck are part of the game. Was that Prince going to score an objective? Was Fateweaver? Do we need to switch gears?
You're at a point now where your opponent is attempting to press his advantage. Can he win? What does he need to do to do it? Can you upend that plan? Is he just happy blasting your stuff? Does he know what to do to actually win?
If you can keep your eyes on the prize and not focus on the unfortunate turn of events, you can still pull this one out. Don't lose hope.
Have you rage quit before? Have you stuck with it despite bad luck and pulled a game out? Anything you want to share?
Ahhhh, it's good to be back. Ta-ta for now!