Have you ever…
been playing music and looked at your music software then your mixer and not seen anything moving then realize 20 seconds later that the music is coming from your browser.
Post your DJ faux pas and goof ups here if you dare lol.
Drunken crossfader confusion. Gets me every time.
Hate it when you cant find out where the music is coming…
Accidently pressing cue on wrong deck & the occasional incident of mixing a tune in only to realise the channel fader is down
I’ve pressed cue on a playing track quite a few times 
I thought I was done with that phase until I did it a couple weeks ago.
gotten angry at a mixer because you thought it was broken when trying to use effects but then realized that the effects were selected to a specific channel and not master output.
Last week during a gig, I told the DJ before me not to press the wrong cue button as a joke… 2 songs after I took over, I pressed the wrong cue.
I haven’t made too many fuck ups myself, other then accidentally cueing the wrong cdj (tho the On Air status of the CDJ2000’s linked into the DJM900 helps with that. CDJ platter turns Red when the channel is “live”).
But working in a nightclub doing lights beside the DJ booth every weekend for 2+ years now, I’ve seen quite a few things.
Dj’s computers dying cause they didn’t plug in the charger. not realizing the CDJ was on Reverse mode. Pulling out USB sticks during a changeover (that’s why I rock SD cards now after too many noobs pulled my stick out mid song). having crossfader turned on and not realizing why sound is only coming out of 1 channel on mixer. leaving the flanger effect on for 5+ minutes not realizing because they were mixing in headphones and not cueing the master channel. having Tempo Reset button turned on the CDJ and wondering why the tempo fader isn’t working. having Master Tempo turned on the CDJ when using serato timecode and wondering why it keeps jumping around the track slightly. I’ve also seen a DJ duo almost knock his partner out by accident thrashing hard at the drop of a song.
Accidentally hitting cue point 1 on the active deck … 
doh!
Leaving the effects on in Serato from the previous track and then mixing it in perfectly only to drop it at the perfect time and then … echoooo echoooo echooooo…
Leaving the filter on the incoming track.
The anticlimax of forgetting to turn the bass back up after a massive buildup that I’ve been effecting the crap out of (oops)
And of course the obligatory taking the needle off the wrong deck.
At least the music doesn’t stop 
The music does stop 
…for me it does anyway.
Yeah, I get DJyslexia… “GRAAAAGH! WRONG DECK!”
^ haha guilty!
as a DJ last saturday:
“Dafuq? What is that song ?! oO no browser or itunes running ? I never heard it before !!” It took me 20" to realize the rock band who played before me found out it would be really nice to jam with me… without asking me before. And no, it doesn’t work.
as a rock musician, in rehearsal :
“Computer is almost out of battery” , by the Mac lady voice, full on, on the soundsystem.
as a musicien, on stage :
“Why the fuck is my computer down ? I plugged it on AC!!!” , turns out the techie plugged me to a light-show outlet, turned off most of the time, it went fully out during time between sound check and headliners.
mixing a record until it runs out and not dropping the fader before attempting to queue the next record. very very bad habit I’m normally very good at avoiding but for some reason it pops up every now and again.
I did that tonight. Thankfully it was at home, and on traktor, with sync. So it just sounded stupid and wasn’t a complete disaster.
I need to add those VU lights to my X1s.
like others, forgetting an fx is in effect
Stumbling over a cable sending the macbook down on the dance floor. unlucky and very embarrassing. luckily though the Macbook survived and I used it for a long time after that.
piss break. 16bar loop. meeting an old friend at the toilett. chatting for 20 min. realizising that the loop is still running. going back to the dj-booth. realizing that the crowd did somehow enjoy the past 20 min with the same loop. (it was sandstorm by darude and they were still screaming and whistling the melody)
similar thing happened to me before. only that i forgot the loop the running song. so when i got back from the toilett the whole florr was empty and the night manager was yelling at me to move my fin ass upstage and play some fin stuff