I have a similar issue...
1. Enter a game jam (or rather the Newgrounds equivalent; this'll my first itch jam)
2. Think of something simple that I can make within the time limit
3. Get really enamored with some mechanic that I came up with
4. Spend way too much time trying to make it 'perfect'
5. Realize that I'm putting too much time in this element, move onto art
6. Spend way too much time trying to make the art 'perfect', same with music
7. Hobble together an embarrassingly clunky "demo" that I can never get around to finishing because I don't know what I did with the project file