I do this as well....I used to think it was because I did meth, (which is very likely in some respects), but that was years ago, stopped long ago, and the behavior remains....so maybe it's not so much the drug, but just how I am.

I've noticed I behave (do hobbies) in cycles. One hobby leads to another, abandon the first for the second, then into the third I go, abandoning the second....then, third leads back to the first again...lol. It's a regular cycle for me.
I've noticed, too, that....despite how much effort I put into my sketchings/paintings.....I NEVER sign them.....O.o...Hmmmm. That signifies something....just never really understood what....lmao.

Shangrala