[Fire-Dragon-DoL]

I think it's the boredom mixed with the vigilance (limiting this at 1-2 year old). Often they want to be "watched" playing, without you playing. It's super boring and you still need vigilance. 1 hour later, puts you to sleep.

To be fair, when kids are bored, they get sleepy too.

[fartcannon]

Agreed. I also (personally) find the positivity draining. I used to be kind of a sarcastic asshole. It was a low energy state. Now I'm an always smiling toddler comedy bot, who at any point in time will sing, or juggle for tiny laughter. I don't have the muscles for it yet and the audience keeps requiring increasingly complex routines.