You can say anything to a guy without creating offense as long as you preface it with “dude.”
“Dude! You look like you got run over by a truck! What happened?”
“Lay off that cheeseburger, dude. You’re pack’n on the pounds.”
“That shirt. Dude. I don’t think so.”
Designating a guy as a dude offers an immediate unfiltered degree of friendship. It does not imply permanency of the relationship. “Not cool, dude. Not cool at all.” But for many males this open and honest expression of friendship causes the dude to pause, pay attention, and most often, accept the observation at face value.
That clear indication of male friendship takes the immediate sting out of any criticism or observation. It becomes something that you are both aware of and it’s OK.
“Dude. You totally suck at that.”
“Yeah, I know. I seriously suck at that.”
“Hey, no worries.”
Do not, however, attempt to dude a female. Your results may vary.