Woman gets upset at the guy she's dating because he acts nice when they are alone but condescending when he's with his friends, now she doubts if he's sincere: 'Am I blowing his banter out of proportion?'

When you start dating someone, you always try to show your best face. You dress nicer, have better manners, and try to seem as interesting as possible. There's nothing wrong with that, is normal to want to show the best version of yourself. Problems start when you are a completely different person from the first date to the tenth one. There is a saying that goes "Character is who you are when you're looking for an audience", and I couldn't agree more with it. Truth is, the real version of someone usually appears when other people are present. 

It isn't uncommon to realize that the person you are going out with is disrespectful by how they treat service employees. When they act demanding and mistreat them just because they think they are more important, that shows you exactly the kind of person your date is. A bad one. If they can't respect someone that is trying to do their job, why would you wanna be with them in the first place? Another way for the truth of someone to come out is with friends, like in this Reddit story. When they want to impress their friends and talk badly about you, that is a sign you shouldn't dismiss. That is their truth. How they actually act, how they are below the perfect image they have been projecting onto you. 

Don't ignore the signs. Trust your instincts. When someone is all nice and perfect when you are alone but lacks manners and good values when they are with other people, distrust! You want a partner that is going to be nice to you at all times, not someone that prefers to mistreat you to look cooler to their friends –as if that was even cool. Don't settle for less. You are worthy of a good person. Don't leave your values behind for someone who can't even be nice to you in public.