i always get that. when i'm content, i appear to be angry and pissed off, and like you say, stuck up. i find out way later that people sometimes are intimidated by me.
so over the years i might smile at people who i walk past, if someone says something to me, i try and be really nice or helpful, i love connecting with people. when i'm a work and get in a convo with a customer, i feel so good, it's such a change b/c sometimes i get so down thinking i'm socially handicapped.