Learn to walk.

This happens to me everywhere I go, and it's equally irritating every time. People walk at a glacial pace while you're right behind them trying to get somewhere. Maybe you have someplace to be five minutes ago or that's just your natural pace. Either way, these people suddenly stop right in front of you, causing a sort of traffic buildup in the area surrounding them. It seems they never notice the trouble they've caused or how annoying it is that they're directly in the way. Come on. The day one of these people stops short in front of me in the DC and makes me spill something all over myself is the day they really get it. All I'm saying is that some of us don't have the time to move at a leisurely pace all the time, and we really don't appreciate getting trapped in your slowzone without warning.