To be able to snap my fingers and have the music I'm thinking of (along with lighting to match) play at the volume I intend it to be. The amount of times I've been at parties or out drinking/at a pub and hated the music being played is countless.
And a mandatory downside (If any) would be that I would have had to have heard the song in it's entirety first.
And a mandatory downside (If any) would be that I would have had to have heard the song in it's entirety first.