I've said this quite a few times, but i'll say it again anyway.
I was a big fan of the original DS games (EBA, Ouendan 1 and 2), i really wanted to play more songs, i even imagined how songs would be if they were in the actual games when i was listening to music.
Then one day we were looking for free games to play with a friend, and we came across "Osu!", and i said "Hey i know this shit, is this real?".
This game is literally a dream come true for me, i haven't stopped playing since i found it.