I get that sometimes. I'm working on turning down the death-ray glare to a look of mild disdain.
I think my expressions must not be very easy to read. My friends always seem to interpret my "having a nice time" face as being angry/annoyed, and my "angry/annoyed" face as being amused, and my "I'm making a joke" face is apparently non-existent. And then some days I'll be in a really pleasant, lighthearted mood, and people will respond with shock or accuse me that I must be in love