Most and Least Favorite Companions?

DAO :
Most - Alistair, Shale, Sten, Zevran.
Least- Leliana.

DAA :
Most - Nathaniel.
Least: Justice? I dunno don't have a strong attachment to any of them.

DA2:
Most - Isabela, Fenris, Varric.
Least - Sebastian.

DAI :
Most - Cullen, Cassandra, Bull, Dorian.
Least - Sera, Blackwall, Cole.

Disclaimer - I don't dislike any of the characters, just don't like them as much as the others or use them.

DAO: 
favorite - Alistair, Zevran, Morrigan, Dog
least - Oghren, Loghain

DAA: 
favorite - Anders, Nathaniel, Sigrun
least - Justice, Velanna

DA2:
favorite - Anders, Varric, Aveline
least - Sebastian

DAI:
favorite: Dorian, Cullen, Blackwall
least - Sera, Vivienne

DAO

Most: Zevran, Wynne, Dog
Least: Oghren, Morrigan

DAA

Most: Sigrun, Anders
Least: Oghren, Justice

DA2

Most: Varric, Isabela, Aveline
Least: Sebastian, Merrill

DAI

Most: Varric, Iron Bull, Dorian, Cassandra
Least: Solas, Cullen, Josephine

DAO: Most: Sten, Morrigan and Leliana (in that order). Least: Alistair and Wynne

DAA: Most: Sigrun. Least: Anders

DA2: Most: Merrill. Least: Sebastian (because he is one-dimensional piece of cardboard with dialogue to reflect that) and... Merrill xD For very different reasons than poor writing. Most favorite, because she is charming, and at times sweetly oblivious and other times shows signs of great common sense insights, Least, because (while DAI showed her to be correct about the importance of the mirror) her path to unlocking the secret of the eluvian, turns that earlier obliviousness into something less sweet, and more into a selfish, irresponsible thing that gets her mentor killed. It's one of the few times Fenris' coldness towards magic didn't bother me, when he tells her he is sorry about his mentor's death... But in a way, that should all just count as generally "best character", because I like how she's written. ​

DAI: Most: Sera. Solas. Least: While I don't dislike her as much as I used to, Viv's still my least favorite character in DAI.

My most disliked character in the franchise (in the games, don't know the comics or novels), is Sebastian.

I voted shale!

DAO
Most Favorite: Morrigan, Zevran and Sten / also liked having the dog.
DLC characters: Anders, Nathaniel and Finn were also good.
Least Favorite: Leliana, Oghran and Wynne.

DA2
Most Favorite: Varric and Merrill
Least Favorite: Sebastian and Isabella just pissed me off.

DAI
Favorite: Dorian, Sera and Bull (and Renn in the DLC). Also Morrigan and Cullen who both joined you party on specific missions.
Least Favorite: Blackwall/Rainier & Vivienne.

This is going to be a hot take...

DAO
Most Favorite: All of them, as in the entire cast, DLC included. However, the standouts were Alistair, Lelianna, Wynne, and Dog.
Least Favorite: None

DA2
Most Favorite: Varric, Aveline, Bethany and Merrill
Least Favorite: Isabella (unnecessary, didn't understand the appeal), Anders (went from being sympathetic and relatable to a terrorist who felt the ends justified the means)

DAI
Favorite: Aside from Varric, Cassandra and Lelianna, no one (I don't count them anyway, because they were already in earlier games)
Least Favorite: The rest of the cast, Inquisitor included. The Inquisition cast just...had zero appeal. I really wanted to like these characters, but...Dorian came close. But in the end, they all were just so....meh and forgettable to me.

Sten is my least favourite (or most hated, hehe) overall, he's a murderous prick who can't think beyond his own skull and the arishock storyline doesn't exactly endear him to me either. Fenris is very abrasive, I'd go as far as calling him bitchy. Bull is a creep.

I don't much care for Leliana. Her obsession with shoes in DAO, probably.

Most favourite is much more difficult to decide. Alistair and Morrigan for their personal growth are far up on the list. Cassandra is a great strong lady character.

DA:I
Favorite: Cassandra - Strong woman with integrity done right for once, sweet believable personality, great voiceacting, beautiful character overall.
Worst: Sera - Stereotypical crazy, self righteous madwoman and over-the-top annoying. Ugh I hate that trope. 

Dragon Age Origins: 
Favorite: Morrigan, Allistair and Loghain -  Very entertaining well written believable characters with great voiceacting. 
Worst: Probably Sten. Sten was ok but the rigidity from the Qun was just totally overdone to an unrealistic level.  

Dragon Age 2: 
Favorite: I disliked all characters but I remember Merrill was the most....tolerable. 
Worst: all but Merrill I guess, in DA:2 all the characters were so insane and over the top....

DAO: 

Favourites: Leliana and Sten 
Least: Oghren 


DA2

Favourites: None (I just didn't get attached to anyone)
Least: None (I don't remember any of them being really annoying either)


DAI
Favourites: Vivienne  , Iron Bull and Josephine
Least: Solas and Blackwall

DAO

Favorites: Zevran,Shale
Least Favorite Oghren because he's gross.

Least Favorite Justice, Oghren

DA2
Favorite Fenris, Isabella, Varric, Aveline
Least Favorite Sebastian.He is blander than a soggy bowl of oatmeal. I really wanted to like him but he's just "there". I don't see much of a point of using him when we've got Varric.

DAI
Favorites Dorian,Cassandra
Least Favorites Sera and Vivienne, although I do have saves where I do get along well with them. In fact, I'm doing my first Seramance with my Qunari and I think it is pretty cute. But I can only take her in small doses, she's a bit too silly/immature but I understand that she's either still a teen or barely out of them and she's young. Vivienne I like sometimes too but sometimes she's just incredibly vicious to companions and I'd rather hear fun party banter than her taking a swipe at someone.