lol, you have no idea what you're talking about, but you sure are adamant about it.
there's an item you want with 6 days left. you don't want to pay more than $100, and it's currently at $20 with 1 bid.
if you bid $100 right now, you'll only be on the hook for beating the current bid. let's say he was willing to pay $50. you're now winning, owing $51. but now he has 6 days to talk himself into paying more. you just played yourself. as a seller, i thank you.
if instead you bid $21 right now, his bid goes to $22. now you bid $23, he goes to $24. this all happens automatically. eventually, 20 bids later, you're now winning with a $51 bid. but he still has six days to talk himself into paying more, but now you have to keep manually coming back to keep up the bids. you played yourself even harder. and as a seller, i thank you again.
if you wait until the end to bid your $100, though, he only has a few seconds to decide if he wants to pay more. if he doesn't, or can't, you still only owe $51.
alternatively, his bid was $120. now when you bid your $100 early (nibble or not), you see that you're outbid at $101. you now have six days to talk yourself into paying more than you want to. yet again, you've played yourself, and as a seller, i thank you.
so, the last option, you bid your $100 with only seconds left. you lose the auction. but you still have your money to bid on the next one.
the right answer for buyers is always to bid your max at the last moment. it keeps the competition from reacting to your bids, and keeps you from spending more than you want trying to out bid someone else.
There's always the chance that nobody else will bid on it, and you will get it for $21, or however much you bid. Why bid $50 then? You're paying more than you have to. You are clearly the one that has no idea what you're talking about. If you want to pay $50 instead, be my guest. If you want to be an asshole and last second bid, then piss off. I don't like snipers. And neither does anyone else.