I always imagine Sarah as naturally unimpressed by Sherlock. Not in the angry way that Sally (justifiably) is, but coolly seeing him as brilliant but also flawed. I think that anyone who's her age and been through medical school etc would know a lot of male doctors who were insufferable geniuses and would have figured out a way of responding to them politely but firmly. But I bet she's glad she doesn't have to work with him.