Why do you remember (or forget) how to do certain things?

Why do I still remember how to ride a bike,
but seem to have forgotten how to ride a skateboard?

And ice skating is in some weird limbo area.
Sometimes I remember (something just clicks)
and I’m skating out in the middle of the ice.

Other times, I don’t remember (nothing clicks) and
I spend most of my time falling on my ass or clutching the wall.

For ice skating, I don’t get progressively better or worse.
Either something clicks in my head or it doesn’t.

Quite strange.