Walking into stuff. We all do it. We all hate it. Not only does walking headfirst into a wall of glass make you feel like the biggest idiot in the world, but wrapping your mouth around a signpost on the street causes an excruciating amount of pain. Luckily seeing other people do this causes an excruciating amount of joy, so in the grand scheme of things it evens out. The dudes over at World Wide Interweb have compiled a great selection of people walking into stuff, so prepare to laugh at the expense of other people's faces.
In case that didn't satisfy your idiot appetite, here's a second course of idiots falling down drunk... there may be some car humping also.