The shittiest of people to ever exist, and if they have any sort of problem, they'll make sure everyone knows. You can't have any sort of private life around a Katie, they've just got to get involved and somehow ruin everything. You're in a relationship? Katie just had to get involved and ruin it. Got a friendship? Katie just had to get involved and ruin it.
Stay away from the Katie's, especially if they own more than two cats.
Looks like a lesbian, owns more than two cats and has a thing for copying other people's music tastes and styles? That's a Katie.