I get really easily understimulated - it's not because I'm bored, it's just I'm used to multitasking and I focus better while doing several things than doing one. Unfortunately, many people (namely teachers) seem to not see the difference, and think that I'm being disrespectful or not paying attention by drawing, knitting, sewing, etc. while someone's talking. What (some) don't realize is that I actually am participating and learning more when I'm doing something with my hands, whereas I drift off into thought, and sometimes into sleep, if I'm without enough to occupy myself.
Also, though I've gotten somewhat better at diplomacy over the years, I'm still prone to pointing out a major problem when I see it, regardless of status or any other factors. As I've gotten higher up in the world, this is thankfully known better as an "eye for detail" and "being thorough," which has worked in my favor. However, I still occassionally run into issues with people who are obsessed with control and being right at all costs, even the truth.
I don't remember names or faces well - a big problem when one's own face (as well as other traits...) is highly recognizable. I once actually got in trouble with my school for not knowing my classmates' names for several months, but that school's emphasis on social skills above all else is another story. I've gotten better about avoiding mentioning the fact that I have no idea who this or that person talking to me is, however.
....And of course, in writing, my tendency towards writing extremely long sentences (stemming probably from trying to fit one idea into one sentence exactly) bugs the crap out of my professors.