Firstly, you have to try and predict when the laughter track will kick in - This isn't as easy as it sounds, sometimes, when I think something is funny, its meant to be a serious bit, and sometimes there is uproarious laughter when I just can't see what on earth it is about.
When you have nearly sussed this, you have to predict the volume of the laughter... Friends is easy, there are about 3 volumes, a "wry titter" a "laugh" and "uproarious laughter" and they all last pretty much the same amount of time.
THEN, you have to laugh along! - This is only amusing when there are other people watching with you, because people have tuned out the laughter tracks, when somebody "real" starts to laugh along with it, at the same volume and duration, then that person starts to appear very very deranged, even though they are only doing exactly what the "audience" are doing.
Try it sometime, with any luck you may be able to make some Friends addicts see that the shite they watch on TV isn't actually funny at all.