"If you come up with a list of many reasons to do something, Nassim Taleb once wrote, you are trying to convince yourself—if there isn’t one clear reason, don’t do it."
[From http://casnocha.com/reid-hoffman-lessons, although I didn't really find the rest of the article as good.]
I had to think about this advice for a bit, but upon consideration, I really think it's right. It seems overly simplistic at first, but I think that's why it works.
Why should we do Fiber? Because everyone wants faster Internet, obviously. Why should I work on wifi? Because without it, I still can't have my faster Internet where I want it.