why will they not sleep?

I officially would like to take back every single time I was a kid and did not want to take a nap or go to bed.

Now- as an adult- I am exhausted. I wake up tired. Go to bed tired. Just exist in a general state of tiredness.

The kids are obviously tired. Eye rubs, yawns, stretches, fussy moods, they are obviously in need of rest. Yet they resist.

I am not really big into strict schedules, but more into listening to a body's signals. Teaching them to listen to their bodies is challenging though.

What do they have against sleep anyway? What is so bad about it? There is nothing remarkable happening that they will miss, why the resistance?