Just wanted to know what your least favourite quest/questline is in skyrim excluding the civil war questline because it svcks... HAIRY TES...

Thieves Guild: the independent jobs are good but I wasn't crazy about the thieves guild main quest

Clavicus Vile's Daedric Quest: the only thing truly vile in this quest was the annoying Barbas that shares all the dogs' tendency to bump you around. Also, it was a pain hiking to the cave the wizard was hiding in.

The Companions quest line.

I think it had genuine potential to be great. But first, it was too short. Second (and worse) it forced a certain action on my character that neither my character or I could have predicted. If you refuse to take this action the quest line ends there and you cannot finish it. This is one of the most aggravating quest designs decisions Bethesda has ever made, in my opinion, and it almost completely ruins the Companions for me.

It's a shame, because I love the Companion NPCs and the atmosphere that surrounds the faction. I thought it had the potential to be more interesting than the Fighters Guild in either Morrowind or Oblivion ...but Bethesda dropped the ball.

If it isn't the Dark Brotherhood questline or DLC, I don't like it.

I'll second the Companions questline though for different reasons. The decision Pseron Wyrd mentioned didn't bother me and I think it makes sense from the character's in-universe perspective. My biggest gripe is how dull most of the NPCs are. There are two deaths in the questline and I didn't bat an eye at either of them. They both came out of nowhere and had little to no emotional effect on me and I'm usually pretty easily worked up over that sort of thing.

Kodlak's dilemma had potential to be really interesting but it comes so late in the questline and has so little screentime, it's not much more than a footnote. I disagree with Wyrd that the questline is too short, I just think too many quests boil down to "Go here, fetch this artifact/kill this faction leader/steal these plans" and don't really propel the storyline forward or develop the characters. That sort of thing should be reserved for radiant quests like Delvin and Vex's Guild jobs, not main story quests.

The antagonists are also really dull IMO. The Silver Hand aren't much more fleshed out than any random group of bandits; their relationship with the Companions isn't explored at all beyond the SH hating the Companion's due to the latter's condition. Heck, even quiet a few bandits have journals and whatnot to give the player insight into their day to day lives, motives, methods and so on. And to top it off, the dungeons are largely pretty standard Nordic tombs that don't stand out all that much. The last dungeon is pretty neat but the rest are pretty forgettable.

And I rather like the Civil War questline, so there.