Let's jump right into it:
1) Calling a girl a slut when she accepts the hug-kiss on the cheek from a guy friend (even if they've known each other longer than you've known her) in front of him.
TF though? Really? You think that's ok? Oh, and yeah, no the bro is "just insecure" and that's totally fine. *crossing arms* grr... *walks off and punches a wall somewhere*
2) Making him feel guilty when he knocks out an entire medium sized Dominoes pizza on his own
It's just really, really tasty pizza. Maybe she's pissed that you might lose your abs. Maybe she's pissed that she didn't get to eat any. No bro really knows...
3) Letting a girl who's obviously jealous of his girlfriend snapchat him ten second videos of her riding a stuffed animal in her bedroom and then opening them (the videos)
Seems a waste to let such good camera work go to waste...
4) Just generally being able to use the word c*nt at all ever in any argument or even about another female in front of females.
It's because you tell a bro he can't that he then really wants to. Why can't we use the word except among other bros? Doesn't seem right...
5) Re-gifting jewelry
The best for last. Would save a bro SO MUCH money especially if he has a lot of girflriends to don in silver, gold, and rose gold ice.