If you’re going to wear long peyos and your tzitzis out, then your ethical behavior, bein adam l’chaveiro, and personal deportment better match your appearance. Cutting corners, pulling shtick, pushing to the head of the line, and similar behavior when you are so obviously identifiable as a Jew is plain hillul haShem. In my mixed neighborhood I am very obviously a Jew, and I feel that I must try to maintain a standard of behaviour that would meet the approval of Shimon ben Shetach (or at least of my Rav). And forget the “pride” business. Ga’avah isn’t a good midah. What you should aim for are respect and dignity and the trait of showing them also for other people, Jew and non-Jew.
This isn’t idealism, it’s enlightened self-interest, because the person who gets a negative impression of you today will act on it tomorrow when they’re interacting with me or any other Jew.
And better believe that your boss – and everyone else in the company – knows how you usually dress, so don’t worry about “dressing down.” If anything, it adds to the negative impression.