Why does parenting have to be so hard sometimes?

I posted about my son wanting to go to camp with the church this week.  I was asking for advice which I got none of here about whether to let him go or not. Anyway, they are pulling out in the morning and I had already let him know I didn't feel comfortable with him going.  Today I said once and for all that he would not be going and I have NEVER seen him so disappointed...ever. 

It's been a rough day because he's been crying and sad most of the day with intermittent spurts of being ok.  He was just getting ready for bed and the tears started again because it hit him again.  He said "I just can't believe I'm not going in the morning." 

I think I made the right choice but now I'm second guessing and wondering WHO I made the right choice for.  It almost seems unfair that I'll be headed back to work in the morning (been off for a week) and he'll be stuck here with my mom or his dad instead of being at camp.

Why does parenting have to be so hard sometimes?...