What do people expect to happen when they mob a celebrity like that? Like what's the point? They're not going to perform a show for you while waiting in an airp

What do people expect to happen when they mob a celebrity like that? Like what's the point? They're not going to perform a show for you while waiting in an airport lounge. I can understand the reverent fan who attends every concert and goes out of their way to do so, and I can understand (in a way) the psychopath who wants to take home their body parts, but I cannot understand the fan that wants to ... fill in blank here ... by mobbing and getting in the face of their idol.