Going to second Freelance and Tyndles on this: in absence of any experience with a fellow roleplayer and in absence of any familiarity with them or their character, appearance and level are two big factors, if not the two biggest factors, in making a snap decision or a judgment call on the fly. That's my outlook and I'm not surprised to see that a few others, at least, share it.
Put another way: if OoC I know nothing of you or your character, what you're wearing and the level of your avatar are going to be very important in how my character reacts to yours IC.
Put another way: if OoC I know nothing of you or your character, what you're wearing and the level of your avatar are going to be very important in how my character reacts to yours IC.