Frankly I do not recall a single service without downtime, this includes banks I use. Yes I'd be mightily upset if said downtimes had lasted for days. 15 min - I do not give a flying hoot as long as it is not too often.
I would literally have no idea if gmail went down from 1-2 am any day of the week. Hell. I wouldn't notice if it was down everyday from 1-2am.