well, if this is the 3rd time its been mentioned then you have to take it on the chin
I can empathise, however. Not so much at work, but throughout my life I have been described as "snobby" or "stuck-up".
It is very unfair, because in reality I am rather shy and struggle in social situations where meaningless chit-chat is required. I just can't do it. Even with family.
Once people get to know me, they realise, but because I guess I am quite hard work, many don't bother.
There was a very long thread on here a few months ago where someone said "they couldn't be bothered with shy people and why didn't they just pull themselves together...or somesuch"
I found that very upsetting and it made me feel worse about myself. Every situation where I am tongue-tied just reinforces it even more.
I think I also have a way of making people uncomfortable, because they sense I just want to get away (I do, but just so I can escape IYKWIM)
I guess you can't change your basic personality. Funnily enough, I am OK at work (except in the staffroom at lunchtime..). My job involves a lot of dealing with the public/children/families and for that I can easily put on an act.
When I have to be myself though, it disappears.
Is your approach actually causing problems in your job? Or was it just an "observation" by your supervisor? Did you ask that ? If it isn't an issue, just a case of personaility traits, then really it was a bit cruel to bring it up and is going to make you very self-conscious. Were any constructive suggestions made ?