He's blinking. If he winks, only half of his eyelid stretches down, making him look like he's been possessed.
@Fantabulous Toaster, or he just squints, but that's a good point
Pixar actually observed Ekaffe Toads (a fairly rare breed of toad native to South America) before they animated the final cut of the movie; mike wasn't 'supposed to be one;' they just wanted to make him proportionate so it seemed plausible to viewers that he could walk around. Ekaffe toads have 2 eyes, but ones like a lot bigger than the other. Anyway, the toads actually have 2 eyelids on each eye. The inner one is for blinking, and the other one is for sending signals to potential mates, rivals, etc. So I suppose they could have done that for Mike and he'd only be winking if he used the second lid. Also, I'm totally fvcking with you guys. 'Ekaffe' is just 'fake' backwards and then I added an extra 'fe' to make it less suspicious. Have a good day.
*Wazowski... (I'm now gonna go take a wizowski with something else that has one eye...)
@Cmnder Shepard, No
@Jakobian, but.... but.... my mom said I could
@Jakobian, wait, I meant Heisenberg Uncertainty Principle
@Cmnder Shepard, I may have hit the wrong picture for this one.....
We've been over this. It's 'bwink'.
@A pet named Steve, that sounds extremely inappropriate. i.e. " I wanna bwink her."
Actually, I know the answer. Either, depending on the situation. Winking is an intentional act done to convey emotion. Blinking is an automatic act to keep the eyes moist or protect from irrigation or whatever.
I heard this somewhere before and can't remember where, so credit to whoever said it originally