When I first started I would begin projects that were a little too difficult for me. The frustration wasn't worth it so I walked away. Later as I improved I would revisit them and finish if I still wanted to. Some I've started are too boring and those go into the scrap pile, we all need scraps right? For whatever reason try not to feel guilt, this is supposed to be fun, something we do for ourselves and our creativity. Put them aside and revisit in a few months. Relax and enjoy.