There's a difference between cutting your losses because an idea just isn't worth your time, and putting in the work to get a bring a good idea into fruition. Sometimes its hard to do this, especially when you have proven to yourself that the idea work. The hard (tedious and mind numbing) part becomes scaling up your idea and convincing other people that its worth something. It takes a lot of tenacity to see even a good idea to the end. Great post!
Of course, you will inevitably tell yourself "I'll stick to it next time; this idea just isn't good enough." The worst part is that the thinking behind this is (partially) correct; if you spend years working on a stupid idea, you won't always be able to build something successful through sheer effort.