We asked a dozen Uber and Lyft drivers the first things they notice about passengers.

For most, it comes down to appearance and how you act.

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Uber and Lyft drivers meet lots of people.

After hundreds — if not thousands — of rides, drivers start to notice subtle differences between passengers. These small distinctions let drivers decide how they might approach a ride: Does the customer want to talk? Should the driver initiate a conversation?

Other times, especially late at night, knowing if someone looks visibly intoxicated can help a driver address how they might approach that particular ride. That is to say, should they be worried about the potential for a cleanup situation.

Read more: Uber and Lyft drivers reveal the things you should never do while taking a ride

Business Insider spoke with nine drivers about the first thing they notice when passengers enter their vehicles. Here's what they had to say (last names have been omitted for privacy):