Fired a guy today

I fired an employee today. I don't know how I feel about it.

On one hand he was a good kid. He was polite, respectful, and obedient. On the other hand he spent a lot of time just standing around even after we explained to him that he needed to stay busy. My manager has been wanting to fire him for about three days. I've been holding him off trying to give the guy a chance. I tried to keep him busy hoping he would pick up on staying busy. Today I put him on rolling and baking pretzels. He did good at rolling them out and twisting them into shape. He was a little slow but that would have changed with practice. But when I stopped telling him what we needed baked he stopped baking. This bothered me but I think what finally tipped the scales was I saw my other employee getting frazzled because he wasn't helping her enough during a rush.

Did I do the right thing? Could I have trained him better? Was I too lenient? These questions tug at my mind. I am not really bothered by them though. I made what I hoped was the best decision for my store and employees.