Q: i want to finish a song but every time i listen to the idea again it already sounds different and i feel like losing the original idea - and in fact i find more fun in playing new song and more of new songs - so how do you actually finish the song when you - or your mood/ vision/ feel doesnt change that fast?
A: keep logging your ideas, but if you don't like them that much then perhaps you should keep improvising/generating new ideas until you get some that still look wild to you, even when you come back to them in the list. beware of what may happen, you will continue generating ideas and get better and better and soon you will have a list of 200 or 300 ideas which actually do drive you wild and you will realize it's impossible to complete all of them in anyone's lifetime