People used to say that I was good with children. I now recognize the key points that made this true:

a) I had energy. If you have energy, it is easy to do fun things with kids. Nowadays, I could not go hunting dandelions and yellow things with a child, because I don't have the energy for it.

b) I had patience

c) I was interested in and cared about the kids

That basically is it. But tired adults simply cannot compete with energetic teens and twenty-somethings in good health.