don't think it is necessary to finish all of them. If you have learnt something in the process ( and had a lot of fun and kept your mind active) then that is all that matters. I don't think you should allow yourself or others to make you feel guilty about having fun your way...nobody apologises for playing too much golf or buying too many clothes or partying or buying expensive football or basketball tickets. I say just go for it. Why should 'works in progress' be any more a bad habit than the other things I suggested?(Hope you enjoy the next project - I have 3 in progress, 4 half quilted and twenty finished ones in the cupboard right now...).