One of the best things I heard at SEED:

"Always start a project with 'It would be awesome if...' that way, you'll get excited about it."

You need to be excited, otherwise, the project is going to suck. A project can have a TON of opportunity, but if you aren't excited about it, then why would you want to work on it? Your project should be fun. Of course, this quote sums it up,

"Be excited and passionate about what you are doing. Failure is less sucky when you are working on things you like to work on"

(Both quotes from Jake and Jeffery from Threadless )