Barrier
That person you always stand in back of that stops randomly or is really, really slow. Especially annoying if you're in a hurry or at school. Can be people or cars.
Example:
"OH MAH GOSH I'VE BEEN STUCK BEHIND THESE PEOPLE ALL THE WAY DOWN THE HALL. WHAT BARRIERS."
"OH MAH GOSH I'VE BEEN STUCK BEHIND THESE PEOPLE ALL THE WAY DOWN THE HALL. WHAT BARRIERS."