[srean]

It has less to do with age and more to do with mental state.

If you are happy, in the flushes of love, feeling safe, many things, even ordinary things will feel amusing, funny, worthy of a belly laugh. On the other hand if you are stressed, under pressure, depressed or angry, then not so much.

Often times I am very easily amused by the most prosaic things and I am not even stoned in anything of external chemical source. It feels good to be that way.

For example, I react very differently to Thurber based on my emotional state. Identical external stimulus, very different reaction.