1. When I had just gotten the game, and gotten to Bleak Falls Barrow. The whole quest was an embarrassment. First off, I didn't know what the hell to do at the first puzzle (with the animal markings), had to get a friend to help me (strangely enough, I had no trouble with the claw door, and knew exactly what to do without anyone else...). Then, after I killed Arvel (by the way, I didn't even let him speak, just butchered him; another embarrassment
), I left the Claw there, and kept moving on. I went all the way back after I realized that I hadn't taken the Claw from Arvel's corpse. To top all of this off, after I defeated the Draug Lord at the end, I didn't know there was a back exit, so I went all the way back to the entrance to leave.
2. Killed Paarthurnax. Not because I wanted to, but a. Wanted to get rid of the quest, and b. I didn't even know what the hell was going on at that point in the game. Mainly because I had subtitles off, and I was talking to my friends, who are loud, at the same time.
3. A similar occurrence to Black Orchid happened to me. This isn't embarrassing, really, but just chaos. I was walking in the marshlands south of Windhelm, and suddenly, I notice some bandits fighting a Giants' camp. I interfere, and after the bandits die, the Giants come after me, until friggin' two bears and a dragon attack for no reason at the same time. I forgot that sometimes I'm not allowed to play the nosy hero.
4. When I was new, and level 2, I aggravated some Giants, and had a stampede after me, which I preceded to move to Whiterun (the location of these Giants were southwest of Whiterun, north of Bleak Falls Barrow).
5. I couldn't...friggin'...find my way to Serana's mother's secret "laboratory" in Volkihar in the Dawnguard questline. I had to look online for it. I'm sorry, I didn't see the switch! All I saw was the game telling me to run into a wall.
That's not nearly all of them, but those are the ones off the top of my head.