Definitely a mental problem. And definitely one that I share...once I get used to the way thing sounds, often find myself compulsively longing to change things and take "the next step," even if I need to invent one just for the sake of exploring it. Changing something is invigorating, allows you to rediscover all sorts of stuff. That, and the upgrade gremlins are insidious little bastards. Never know how they're going to get their hooks in you -- and yes, do frequently seek to ambush you when your guard is down, bored and complacent -- but they're tenacious once they get the drop on you.