Facebook reach-around.
When you 'like' someone's Facebook post just because they 'liked' yours, even though you think it's the worst thing ever.
'Like' on a post about their cat's butt because they 'liked' your post about your ex's face.
'Like' a status about how much they hate Mondays because you're too lazy to think.
'Like' a post about their mom's hair because you're too cheap to buy a real lunch.