Of course it is--for all you know, I could drop dead if I was being too nice to someone for too long.

[Is he being sarcastic? Who even knows--] And maybe it is my business to know. You wouldn't want me to just use it more often as an insult that actually does get under your skin, right? [Like seriously if given a legit reason for why it bothers you, then he...well he might still call you that but it would be less frequently than if you're just overreacting to a petty insult.]