The amount of times I've seen passionate people make bad technical decisions in the name of trying something exciting is too many to count. I obviously agree that passion is valuable, but not without faults. I think I'm better in some ways and worse in others due to the way I approach the job.

Have you ever met certain singers at talent shows? Even if they'd be better at it than if they wouldn't have the passion, there's also a certain bar one should be able to reach.