Certain instances of bad grammar really bother me. For instance, from Streams by Haken:
Streams of blood like liquid love is are rushing to my brain.
It wouldn't affect the lyrics at all if it were corrected. However, here are instances I'll forgive it, like in The Dear Hunter's The Line:
It's the end of the line for you and I.
Really it should be "you and me," but I'll let it slide because they'd have to change all the lyrics to fix it.