One too many mimosas?
I may've driven to work behind Drinky McDrunkerson this morning. The driver in front of me couldn't seem to keep between the lines despite the unusually wide lanes here (everything is bigger in Texas!). He would center it up, then expertly glide his way over to the rumble strip, then ease back into the roadway. This went on for about 15 minutes before he swayed across the centerline, into the right lane and just decided to stay there for a while. He was kind enough to get off at my exit, then stop a "Yield to ramp" sign, although we were the ramp and there was no other traffic. To his credit, he did have out-of-state tags, but I'm pretty sure it's customary to drive between the lines in most other states.
I also had the pleasure of driving behind an "over-braker" for a while. These are my favorite. They swoop in from another lane, barely sneaking in between me and the car ahead of me. Then, once they've filled that little gap, they hit the brakes because, uh oh!, they're too close to the car in front of them. Once they've made a little space for themselves, they realize that, "Wait a second... the only reason I'm in this spot is that I cut that dude off because he was following by exactly a car length! What if someone else cuts me off? I better fill that gap in front of me!" So, they speed up until, uh oh!, they're too close to the car in front of them. Rinse, repeat.