Tauto: bazillions of endless bugs
Is a bit of an exaggeration and like you with all the mods and unofficial patches,have no problems.
No, it's not an exaggeration. See my previous post above and the link to the Unofficial Skyrim patch and the tremendous number of bugs it fixes in the game. They are not all game breaking bugs, but they are bugs nonetheless. I personally experienced about 10 game breaking bugs in my first and only playthrough of the game. One of them required me to work around the issue by restoring a 2 week old savegame that was from prior to a malfunction of the game engine as there was no way to fix it otherwise, so I lost 2 weeks of gameplay as a result which was very frustrating. A few other game breakers lost me a few more days of gameplay as well. The other game breaking bugs I encountered were things that were all able to be worked around by issuing commands in the game console. That is fine for PC players such as myself but I can't imagine how frustrating it would be for console players who I do not think have the option of the console.
One example game breaking bug that I remember, was a quest where I was supposed to kill the bandit leader of some tower in the eastern side of Skyrim. I don't remember the name of the quest, but I had already been to that tower and killed everyone there already before I was even given the quest. So when I was given the quest and went to the quest marker there was nothing to do. I could not kill the already dead bandit leader because well, he was dead. The game would not credit me for having killed him so I could not proceed to complete the quest, and so the entire questline of the game beyond that point was not available to me. I had to google search to seek solutions to the issue which lead me to one of the two main wikis for the game as well as many forums out there to juggle the various options different people who did in fact experience this bug also came up with to work around this issue. Now, for people who played this game and did NOT in fact kill that entire bandit lair before getting the quest - then they would most likely have not encountered that bug. It doesn't mean the bug doesn't exist, but that the choices they personally made in the game did not trigger the bug that does exist in the game.
The solution to that bug, was to go to where the bandit lair is, find the dead body of the bandit leader, which was still laying around, then enter the console, click the mouse on his dead body, type in some obscure command which tells the game to bring him back to life, then kill him again. So I did that, it transported his dead body 50 feet in the sky above the tower I was in and he fell on top of me then fell out of the tower and died again. The game registered his death, and I was able to go back to the Jarl or whoever and get credit for killing the bandit leader.
I experienced a dozen or more very similar game continuity bugs like this where if you happened to do certain random actions in the game before receiving and starting a particular quest, that you may not be able to finish that quest.
Then there was another incredible bug where at a certain point one of The Companions would draw his sword any time I came near him for no particular reason and enter talk mode. If I exited the conversation with him, he would chase me and draw his sword and enter talk mode again. You couldn't get away from him, he'd perpetually follow you and enter talk mode. There was no complete solution for this bug and it made some quests impossible to complete. I had to try to run fast and use dragonborn powers to warp myself at high speed away from him and into areas he could not get to until he stopped following/chasing me. This did not affect the main quest line so it wasn't specifically a game breaking bug, but it completely destroyed my ability to proceed further in the optional companions quest line.
The last bug I experienced in the game was when I made my choice very very late in the game to choose a side in the war and was following the quest line to fight the Imperials. I was supposed to break into a prison to release someone, but no matter how I approached it, I would get discovered by the guards. I got frustrated thinking I must be doing something wrong so went to look for tips on how to get past that mission. It turns out I wasn't doing anything wrong, there is a bug in the game. Everyone who plays it doesn't experience the bug and it is not clear what causes or triggers the bug, but many people end up stuck where they can not complete this part of the game and the only way to get past it is to use the console to 'cheat' past the game bug.
Then there is the bug in the game that lets you trivially walk through walls by holding a basket or dish in your hands and running at high speed into walls...
The list of bugs goes on and on and on.
Despite all of these bugs and my kicking dirt at Bethesda for them above however, Skyrim is quite simply both one of the best as well as one of the buggiest games I've ever played. I'd recommend anyone and everyone play Skyrim as it was fantastic, but I could not do so and sleep at night without also warning them how tremendously buggy it is and to be prepared to use Google to work around inevitable bugs they are likely to experience. If someone has no patience for that sort of thing then they might not want to bother perhaps, but the game was so incredible that despite the bugs, I say it is worth it to play but to have patience for the occasionally game immersion breaking inevitable bugfest that will happen. :)
What would be even more amazing though, is if after N years (for some value of N), if companies like Bethesda would release the complete source code of their video games and let crazy enthusiasts out there tackle fixing all of the bugs that are known in these games while armed with the best information available - the source code. It is amazing just how many bugs people have fixed in Skyrim and many many other games by hacking game executables, data files etc. But one can only imagine how good of a job they could do if they had the source code. :)