Well let me start by saying, I am not a man. LOL
But to me, in my opinion, based on my fiance'... I'd say that the most difficult thing is growing up. I'm not bashing men! I'm just saying that when a boy hits that age, all day they think about sex and I would have to say its hard to get past that! I never experienced it but I heard from a bunch of guys that its a very hard time. They have to pretty much control themselves.
The easiest thing about being a man, I'd have to say, based on me being a woman, is not baring children!