Time Flies When You're Listening to Music
A new study from Clermont University in France shows that music affects how accurately you judge the amount of time that has passed. In other words, musical sounds were judged shorter than neutral sounds of the same duration. Although the authors don't have a clear theory about why this occurs, they refer to this study, which shows that emotional sounds were judged longer than neutral sounds. So music makes time pass faster while emotional sounds make time pass slower, regardless of whether the music is cheerful or melancholy.
Incidentally, time also flies when you're reading swear words.