There was a play on Radio 4 a while back, where a guy orders a sandwich but it never arrives. Deciding that leaving would mean wasting the hour he's already waited, he stays in the cafe for years, waiting for the sandwich to arrive.

Read 'Eric Ries - The Lean Startup'. Your time at this startup is not necessarily wasted, if you've learnt stuff, networked, and somehow helped you get your next job.