For me there are three main things -

Arguing with myself constantly - I should do this and I should do that and never do it and then get mad that I didn't do it.

When I buy one thing, I buy 10 to go with it, or I don't buy anything at all.

Focus. My mind is all over the place. I start watching one movie, turn it off, watch another movie then turn it off and go back to the first movie. I have over 100 half watched movies.