1. You feel more connected to them than ever because you survived that batshit fight. "'What can't we get through?!' champions coming out of the ring while high-fiving" sex is a very, very good kind of sex.
2. All the anger you were feeling has already made you (physically) really hot. The feeling you get when you're pissed off and when you're turned on are so similar in terms of your body heat rising and feeling short of breath, so flipping the switch for something good instead of evil (though anger isn't technically evil and is a basic emotion) is kind of like performing a casual miracle.
3. If you're still kind of pissed off at them, you can use that. Hate-fucking someone you actually love most of the time is basically just sweetly beating the crap out of them with your vagina, which is a win-win if ever there was one.
4. If your partner was wrong and they know it, they overcompensate big time. When your guy knows he screwed up, he also knows all the right ways to make it up to you. I'm talking about sex ways. Not, like, bringing you doughnuts, although that's cool too.
5. It puts the dumb thing you're fighting about in perspective. Yes, this person does not do the dishes and when he does they are somehow still dirty, but also you love him and he goes down on you in a way that is probably best described in a power ballad by Adele, so whatever.
6. You can remember tonight as the night you had awesome sex and not as the night when you had the same argument you always have about why he is still friends with Greg even though Greg is the worst and he complains about him all the time.
7. It can put a bandage on a super-huge problem with a super-huge orgasm. Not all make-up sex happens when you've both totally dealt with all of your issues, but it can be a really nice reprieve from a seemingly insurmountable issue between the two of you. It's hard to stay frustrated with recurring relationship issues when you're both making each other come a lot, and you can keep trying to deal with it later.
8. It's a great way to end a fight you had no idea how to end. You ever have those fights where you don't even know what you're talking about anymore but you both seem really annoyed? Kissing the person aggressively is a great way to get away from what was probably a nothing-at-all disagreement and a move toward the bedroom to do it.
9. If something weird happens during sex, you can laugh about it, which helps you let go of whatever anger you might still be holding onto. Laughing during sex always feels so awesome, and laughing helps you release all the pointless tension still remaining in both of your bodies after your very intense and passionate fight about his horrible taste in throw pillows, which he does in fact have.
10. You get to be waaaaay more aggressive than you would normally be and never have to explain why. If you're usually kind of timid or let him take the lead, all bets are off now because you're still kind of mad. So it will come as no great shock to you or to him that you're being a little bit bolder and grabbing his hair a little harder than you normally would. In a way, it's like getting to wear a sexy Halloween costume instead of your normal clothes: All bets are off and no judgement is allowed. Actually, if you wanted to dress up as a sexy cat during make-up sex, he'd probably be into that, so keep that option open too.