Doesn't bother me on a massive tv, when the ratio isn't 16:9.
Does bother me on a (relatively) tiny iPad sized screen, so I make a deal with the devil and, if the source is 16:9, I distort the ratio in, for example, Infuse. Accordingly, the actors/scene look marginally taller and thinner than originally intended, but not so much they all look like basketball players (not the other ratio option that merely expands vertically and you lose the sides). I'd be dead against this on a massive tv as you're bastardising the creators vision, but in the context of watching on a 9.7" or 12.9" screen, I'd rather it fill the screen. Films etc aren't really made for such small screens anyway, so it's hardly a culture crime.
On really wide source material I leave the black bars visible as the distortion is ridiculous.
I remember Tarantino saying he was horrified at the thought of anyone watching one of his works on a phone or tablet, heh!
Vaguely related, I'm very happy Apple stick with 4:3 personally. Had 16:9 tablets in the past briefly, everything except video suffers. Not a worthy trade off imo.