You can’t put too much stock in first impressions. People who might seem arrogant or pompous when you first come into contact with them could be sweethearts in their everyday life. You need to consider context and take any observations you make with a grain of salt. Give them another shot. Maybe they were in a bad mood, maybe they had a headache, or maybe they tried to cover up their insecurities by coming on too strong. Form a conclusion too quickly and you could miss out on getting to know a cool person.