There is also an element of uncertainty. Sometimes you are ready to pay more but you are unsure of the value. Others bidding more, may convince you it is ok to

There is also an element of uncertainty. Sometimes you are ready to pay more but you are unsure of the value. Others bidding more, may convince you it is ok to bid more. For example, foreign jewellery on which you are unfamiliar with the hallmarks. You don't mind paying $200 for it if it is silver, but is it ? Of course, rationally, for the raison you gave, you should not use that, but conversely if you are familiar with a certain type of popular auction you start to see some patterns. An object that breaks it is either a bargain, a fraud or you were simply early. For example, silver never goes for less than scrap and genuine auction never really shoot way over boot sale value. Or maybe I rationalised my irrationality :-)