Two-factor auth gets old really fast when you have to use public computers in a setting like a college library. I had turned it on for a while, but turned it off when I had 5 minutes to print out a paper that I had emailed myself (yes, I still do that) and was fiddling with my phone to get the damn PIN. Never again.
Well, is that 5-minutes-to-print an edge case or a more than occasional situation? If the latter, how hard is it to create an alternate email account in which you send non-confidential emails/docs on the spur of a moment? If it's an edge case, it seems like a trivial one for reducing your security so much. As your documented online data grows, the chance of being hacked only grows. And once you've been hacked, there'…
Seriously though, when you have to enter the PIN multiple times a day, it gets annoying.