One of the many advantages of cleaning up my studio is that I uncovered some paintings that had been buried under what appeared to be years of stuff. Some I tossed, some I like and some need more work.
There is a rule of thumb to keep in mind as you create art. Out of ten pieces: 2 or 3 will be ones you rather no one else ever sees; 6-7 will be good and you could put 'out there'; only 1 will be one that you think is wonderful and that you are very proud of.
So don't feel bad when something just does not turn out. It is OK to throw it out, paint over it or reuse in some way. Don't expect every piece to be a masterpiece, life just doesn't work that way most of the time. Keep on creating - the more you make the more really good items you will have! Keep creating!