When we had our son (the boy was first) my best friend pissed me off so bad I didn't talk to him for several months. What did it was he had already had 2 kids with a 3rd on the way. I guess the boy was 6 months old, and we went to go see them down in the taint of NC (Lumberton, where he was a pastor at the time) for the weekend, and he asked how it was going. I said "Rough! He gets up at 2am and 6am and we're both exhausted" He laughed and said "sorry man, but you're not a REAL parent until you've had a second and have to manage 2 of those little monsters"
Call it sleep deprivation, a sandy bergina, whatever you want to say but as a new parent with my world having been just turned upside down, that chapped my ass like a 4ft flame. I told the wife to load up we were headed home (had just gotten there too)
Years later when we made it home from the hospital with our second, there in the middle of the night trying to feed our #2 night dweller demon spawn, I actually forgave him for saying that