Why is it, that A mk4 golf GTi 1.8T that has more than 100k on the clock, is worth alot less than one with 90k on the clock.

Been looking at a few on Autotrader, and there is a massive difference in price between cars with sub 100k milages and those over 100k. Does the 1.8T explode at 101k or something?

Considering getting one when my time on the ship is up, purely so I don't have to get the train home But would rather buy a decent Mk3 rather than a Mk4 thats about to explode