or it comes on on the radio

YOU. ME. WE ARE NOW BEST FRIENDS.

Typically me and my sister.

It is cooler when they also sing the bit you were up to...

you you are in my mind :O

I have a theory on why this happens:
Somebody starts to think of a song for some reason. You hear them humming/playing/whistling/singing the song and so does someone else. The thought of the song is passed through any social group until two people realise they both have it stuck in their head

demi!!!!

this happened a lot after "Let It Go" was released :D

Is that Sonny with a Chance?

SOULMATES