I saw a topic asking about this in regards to the Justice League on the DC forums, thought I'd make the Marvel equivalent.

Who is your all-time least favorite Avenger, of any era?

It can be for a variety of reasons such as: the character didn't belong, didn't fit in well, got on your nerves, you just flat out hated the character, etc.

It should be noted that you don't have to hate the character itself necessarily, but hate them on the Avengers, how they were written, and so on. Of course, hating them outright is a perfectly good reason.

For me:

The Sentry

Ugh, this guy was such a blight on 2000s Marvel, especially because Marvel pushed and shilled him as hard back then as Captain Carol is now, only even more unlikable. I don't even get it, what did Marvel see in him? He was a Superman rip-off, who had none of the depth or likability, who kept getting even more powers at random than his Silver Age counterpart. Everything about him is bad writing on an elementary level. Of course, he was also forced onto us at every turn, and the Brian Michael Bendis' New Avengers run is something I'm very reluctant to go back to just because he's in it. Thankfully, I think Marvel caught on. The last thing Sentry ever did was a short-lived mini and I hope to God they don't have him return to the core again.