How to decide what to write when you like "everything"

I think one of my biggest problems as a writer is my indecisiveness and inability to finish. I try to follow the "write what you'd like to see" advice, but I love a ton of movies from just about every genre.

When I start writing, just thinking about another movie makes me want to write something like that. I'll go from wanting to write a big budget sci fi action script, to contained horror, to romcom, to heavy drama, to mystery tv series.

And the thing is, I know not all my ideas a good, but I feel like some really have potential, but I still can't stick with them. Any tips would be helpful. Thanks.