I ran into a building (had some strong vampire dude in it, almost a half screen over from Whiterun) and there was two dragons, one ran like a bitch (like he didn't see me or soemthing) and the other just sat there letting me peg it with arrows, till I nearly had it dead, and then went to flopping like a fish and the game started chugging around 4 frames per second. Yeah, lots of glitch stuff happened there, I thought the game had crashed, but I loaded a save and it went away....well, all the glitches did, except the dragon still flopping like a fish out of water LOL
I've been doing a LOT of exploring in this game, I mean, the save says I've dumped 160 hours into it, and I've only done like 2 or 3 main quests, and one thieves guild quest. No ohters. But I've run into a lot of sidequests I cannot complete because I had long since cleared out the dungeon they want me to go to, so their stuff is gone. (I thought dungeons were supposed to repopulate?) That's the most common problem I run into.
Of course, there's the leveling thing which I considerr a glitch. I mean, I expect the enemies to level with you, so you don't just go wipe your ass with them or something. I don't expect my one hit kill weapons to all of a sudden go to a 20 hit kill and me to get killed in only one or two hits ever time I level up though....even with legendary weapons and armor, and a highe enough armor and weapon rating to have all the multipliers unlocked.
Oh, and why no silver weapons? I have one silver sword I got from a cave full of wearwolves, but there is no option to upgrade it (despite there being silver ingots and ore) and no option to make them at all, and I have ALL the armory perks unlocked. Light dragon armor for me, upgrading it as soon as I max out my enchantment and get a few more maxed black soul gems.