The sickness of actually liking your job

My friend called me a few minutes ago. Friend: Hi J, what are you up to?

Me: I'm working.

Friend: I thought you were sick?

Me: I am.

Friend: So why are you at work?

Me: I'm at home, got a fever and feel terrible.

Friend: ...and you're still working?

Me: Yeah.

Friend: What the hell is wrong with you?!

Me: ...I honestly don't know.