Have you ever had a song idea that you tried expanding, but you would up using the new thing for the basis of a different song, and then when you try to expand that new song you make another part that you decide to use for a new new song idea and so on and so forth until you have a billion trillion song ideas and are drowning in unfinished projects? How can I make this stop?
if you get an irrelevant tangent, log it separately in your songs list, but keep working on the one you were working on and keep searching for what is right for that one