Best feeling right there when dealing with requests... get a request, point to the screen showing them you got it already cued to go, and they respond with you're the man or this is why we love you. Wont always happen, but great feeling when it does. Also shows you really understand the crowd and where they want to be taken through music.
And even changing to it if it's not queued could be a good thing - but I will not risk an event on a stream.