Birthday's for Him, Birthday's for Her--above the greeting card displays at every store several years ago.
Exiting instead of exciting--I see this all the time, and it drives me nuts
Rein, reign, rain--Our church puts the words to songs on a screen. We used to sing a song about God's sovereignty, which obviously would use "reign", except they insisted on using "rain", as in "Send Your Rain", when we were not talking about the weather. When this was pointed out, the person doing the songs went back and checked, and found that the songwriter wrote the song that way. No matter which way they put it on the screen, someone complained. At one point, they had changed it so many times that it was spelled one way in some verses, and the other in other verses. We don't sing that song anymore.