I wonder if the fact that the whole main cast has seen each other naked multiple times affected the friendship dynamics at all.

No, I think the problem would be the number of times this conversation took place:

"Wow, that looks like a painful scar, how did that happen?"

"Well, I was trying to protect my best friend and suddenly I hear, 'Don't lose your way' blasting out, whereupon some PSYCHO with half of a pair of scissors tries to gut me like a trout!"

"Oh, right, right. Umm. Have some lotion."

"THANK YOU."

"It's the least I could do."