Unless you're a glutton for punishment, you probably don't want to pursue a relationship with someone who offers up excessive criticism during your date. Perhaps he looks at you from head to toe then smirks, or she sarcastically questions your mannerisms, mode of transportation, where you live or why your parents gave you your particular name. If he's rude to the wait staff and constantly complains about the food, he may have underlying issues you don't want to be bothered with. You'll also want to make a mental note if your date derides other people's features, clothing, cars or lifestyles. Do you really want to hang out with a person who enjoys putting others down?
The temperature on your date is also an important consideration.