system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What does a DJ actually do apart from choose the next song?

Referring to both DJ's at parties/clubs and DJ's at concerts.
gpt
A club DJ has one job: keep people dancing. Sure, he can simply create a playlist and let them play through with a simple pause between each track, but that is not interesting to the ear and, more importantly, it would interrupt the dancing. It would be even worse if the tracks played one after the other with no break between. One moment, you're dancing perfectly in time with the song, and the next you're completely out of step. It's far too jarring and it makes for a bad time on the dance floor.

Instead, a DJ will create a playlist and blend it together into one continuous song, allowing the people to dance without obstruction. To do this, the DJ adjusts the speed of the tracks as the playlist plays so that the tempos match up evenly. This allows the songs to play into each other seamlessly, thus, keeping the party going. Creative DJs can enhance the performance by finding surprising ways of mixing the tracks, utilizing anything from effects to original samples.