Sometimes grammar errors in a song frustrate me a lot, because it often makes the song nearly impossible for me to sing along to, if the correct word has more or fewer syllables. The one that's been haunting me all morning:
The sign said stop
but we went on wholehearted;
it ended bad
but I love what we started.
But, it should be "wholeheartedly" in the second line. So, when I sing along, I end up saying "wholeheartedly" and then I've missed "it" and might mess up "ended" while I try to get back on track. It's very difficult for me to consciously say one little thing incorrect out of a mostly-correct larger block of text, because I've trained myself to automatically fix little errors like that.