Scammer: "I'll give you this expensive item for a really good price."
*Scammer shows item in trade, waits for victim to put up money*
*Both go through to confirmation screen*
*Scammer declines*
Scammer: "You need to be faster to trade or I won't trade with you."
*This continues a couple of times until the victim is putting up the money and clicking through the confirmation screens as fast as possible, scammer is now happy with the lack of attention given to trade details*
*Scammer substitutes a different but similar item*
*Victim goes though trade as fast as possible without checking to make sure the item offered is the same*
*Scammer accepts this time, victim receives something other than was being offered the previous times*