This really grinds my gears, but i can't quite work out why as on the face of it its kind of sweet.

This stems from a couple of instances recently when i've been listening to music on the bus/tube/train with my ladyfriend (one earphone each) and she has started singing along to whatever. Now she's got an ok singing voice, but it really pisses me off.

i think its partly because i don't like imposing myself on other people, and the person sat next to/behind us might not appreciate it, and so it annoys me that others aren't considerate that way. also it kind of ruins the song a bit because inb one ear i've got the song, and in the other i've got someone singing the song and forgetting half the words. plus she isn't as good a singer as she thinks she is (who is?).

am i right to be annoyed when people do this (it also annoys me when strangers do it, but to a lesser extent), or should i just get over it? also should i tell my ladyfriend how much it pisses me off or let it simmer?