MCs/comperes of clubs will recognise the occasional phenomenon of the floor singer who, when told it's one number per performer and that time is short, will either (a) say, "Oh, could I do two very short ones?" or (b) ignores the time constraint and sings an inordinately long song. The two short ones, inevitably, are not short. Such people concentrate only on their own needs and ignore the feel of the whole evening.

My action, when that happens, has been to exclude them from future floor spots - which is actually less drastic than some MCs I've heard in years gone by, who shouted out something like "Get a move on!" in the middle of a number!

There's absolutely nothing wrong with performing a long ballad, but context and ability are everything.