There is only 1: emotion.
When a potential buyer watches an item for a week, feelings begin to form. Maybe every couple hours or, at the very least, every day Buyer checks in on Game; makes sure Game is still there and it’s doing okay; makes sure Game isn’t getting too much attention. With each day, the relationship becomes stronger. unfortunately Game doesn’t give back the same love and affection to Buyer. But Buyer doesn’t care. Buyer likes this abuse. Buyer will do what it takes to own and hold game when all said and done.
it would be interesting to see what impacts longer auctions have on ending prices compared to shorter auctions. I’m just being silly with what I said above, but I would speculate that longer auctions do help to emotionally invest buyers than shorter auctions.