If you call me a purplito (the little purple one), I should be offended. I am simply not aware or conscious about how that phrase can hurt me psychological, even though you are using it an affectionate and friendly way. Is that it?
Joseph Tham You asked for how something was POSSIBLE, and I explained how it was. Now you are raising a different issue, namely whether you SHOULD be offended when you FEEL that you aren't.
However, just because you don't feel offended doesn't necessarily mean that you aren't. You could be unconsciously processing the remark as offensive and that might manifest itself in certain behaviors, similar to the situation with unconscious desires, beliefs, or fears. Of course you may just be thick-skinned and impervious to insults, which also admits of several possibilities, e.g. you could be insensitive or else you could rationally take such things to be beneath your concern. The conceptual space allows for numerous possibilities.