Happens every now and then. I seldom watch TV (prefer to watch series and such from the computer), but when I do it's either commercials, borring programs, effing TV shop / Twins or replay of other stuff I saw last time I put on my TV.
Happens all the time, if my flatmate is here his TV is running more or less constantly in the background, on a commercial channel that seems to broadcast either How I Met Your Mother, Two and A Half Man, Big Bang Theory or advertising.
But the older I get the more I admire all the public channels (like Artè) which often have no ads at all. A film or series gets a whole lot better if there are no breaks every 15 minutes.