1. "You're not that strong."
Unless you're talking about a Superman-esque feat of strength like lifting a building, you've just made him feel inadequate.
2. "I'm so much taller than you!"
It doesn't matter how tall a guy actually is, calling him short, even if it's just because of the shoes he's wearing or something, bruises his ego. Way to make a guy feel smaller and less like a strapping, muscular lumberjack (even if he isn't one, most guys have a strapping, muscular lumberjack complex).
3. "These condoms aren't too big for you, right?"
Never call a man's length or girth into question, at least to his face. That goes for his whole body, and doubly so for his penis.
4. "Is your hairline receding?"
If it is, we're probably not going to be able to pull off being bald as well as Jason Statham, star of The Transporter, Transporter 2, Transporter 3, and Gnomeo & Juliet.
5. "I can't cuddle you. Your body is hard and soft in all the wrong places."
Like a bag of garbage that someone also carelessly threw recycling into.
6. "Why is your beard so patchy?"
You just asked, "Why is this part of your face dumb?"
7. "How do you have this much hair?"
This immediately makes us feel like that hairy guy in Borat.
8. "Oh, wow. You can really do a pull-up?"
Either we can't, in which case you've just rubbed salt in the wound, or we can, and you're just saying we look like we can't. Mean either way.
9. "I don't see how you can win in a fight against a bear."
Don't take this dream away from us.
10. "You don't actually know how to change a tire, right?"
All men know how to change a tire. If they don't, it is because they are 6-year-old-boys (literally).
11. "You have a really unique penis."
Is that your way of saying it's weird? Penises come in all sorts of shapes.
12. "Can't you just finish yourself off?"
We can. It's called masturbating. It's a thing we can do whenever we want, like when you aren't in the room to do fun sex things with us.
13."I wish I could find a boyfriend that's as kind and funny as you."
You can. It's the person you're saying this to.
14. "Your sister is hot."
This sentence means we automatically get to fight you (if you're a guy) and we automatically get to feel really weird about the two opposite feelings going on inside right now (if you're a girl).
15. "Have you ever thought about waxing your back?"
Well, now we have!
16. You're like a brother to me."
What you said was, "I feel really close to you and your relationship is important to me," what they heard was "I don't find you sexually attractive in any capacity." Even if, deep down, we know this is true, it still stings.
17. "Wait, you actually go to the gym?"
What aspect of that is shocking to you? The part where we successfully navigate there or where we somehow operate the equipment?
18. "Is your girlfriend your sugar mama?"
This is a great one if you want to offend multiple people on multiple levels: either you're insinuating we aren't progressive or you're hitting a nerve. At the end of the day, we love having a successful partner.
19. "Why did you just sit on the couch and play video games all day?"
Because it's Sunday and we like doing it, that's why.