It's related, I think. You're working on something that will take a while, and even though you're doing the work, it's still delayed gratification. Worse, it's

It's related, I think. You're working on something that will take a while, and even though you're doing the work, it's still delayed gratification. Worse, it's often the schlep, as pg puts it - that unenjoyable middle ground of work work work with no tangible reward. But the new thing... it's shiny. It's immediately gratifying to say "I'm going to start on this new thing that won't suck like the old thing sucks."