Why taking pics of bands on stage is a complete waste of time, film and effort

It's always tempting. Your favourite band is on stage and you want a souvenir pic to prove you were there. You whip ot the disposable camera, hold it above your head and press the button. Then, weeks later, when you've found the camera again and taken the film to Boots for processing, you discover that your carefully framed shots are of the back of someone's head. This is why the pros have huge telephoto lenses and get to stand in the photographers' pit right infront of the stage. Here's some of my own pathetic attempts. Let them be a lesson... You can click on them to see them full size if you really want to.

Loop, on the main stage, 1989. I was right at the front for this one...

Leatherface, 1993, on the second stage. No, really, it IS Leatherface

Not a clue who this is, but the year was 1998, second stage. Possibly 3 Colours Red. Or The Fall...

A second attempt at capturing Loop, main stage, 1989. Actually worse than the first try

Trying the arty approach by snapping the Supersuckers on the big screens by the main stage, 2000. Another partial success...

This wasn't even a band pic, but a shot of some huge, inflatable figures near the bungee jump. No, I can't see them either...