because thats how ebay is SUPPOSED to work.....
everyone sniping an auction at the end makes it all very pot luck, if everyone bid the maximum they were willing to pay for the item, it would make it very easy for people to see what it was likely to be going for, instead of everyone having to wait for an item to go into its last 30secs and all try and snipe each other.
sniping also causes people to bid more than they actually want to (or sometimes can) pay, just because they dont want to be beaten in the last seconds of an auction.
im sure we have all paid over the odds for something at some point or other, then though, #!#!#!#!, why did i do that?
Now, if i want something on ebay, i bid what i am happy to pay. if i win, all good, if not, no sweat.