First impressions do count for this, I mean, whoever you are referring to may dislike any small detail that you do, even when it seems like you've done nothing! You usually know whether you like who you are talking to within the first 10 seconds and it is hard to fix this if your first readings are negative...
If I was you, I'd just ignore these bullies as your reaction acts as a fuel to them, if they get no response they get no fuel meaning they'll either stop, or try find someone else to pester.
