Recently, I was sitting in an overwing row (11) but boarded near the end of the boarding process. I was going to put my bag over row 5, but the FA assured me that "there was lots more space toward the back." I believed her (instead of my own eyes) and ended up having to inconvenice some people by rearranging their luggage over my row. Even though these people had daftly (and selfishly) placed coats and awkwardly shaped items in the overhead bin instead of under the seats in front of them, I felt bad having to rearrange this stuff so that my regular sized rollaboard would fit.

Moral of the story: don't believe the FA when told "lots more room" at the back, if your eyes tell you something to the contrary.