Dangling participles. I'm guilty. I confess that sometimes I leave mine all exposed.
Example (I must admit, I stole this from here because it is so dang funny):
Flitting gaily from flower to flower, the football player watched the bee.
"If you said the last sentence to the football player's face just the way it's phrased above, you could end up a bloody lump of pulp lying on the Astro Turf, because he might conclude you think he "flits gaily," a thing most people in his profession don't do, at least in public."
So, remember, keep your participles in their appropriate location:-)