What is a “never again breed” for you?
A breed you may have struggled with and have decided will never fit your lifestyle kind of thing.
Probably an Akita, just because I had trouble restraining one when I volunteered at the pound, only dog I ever needed help holding onto. She wasn't aggressive (towards me though she got put down when a vet tech claimed she growled at her) she just had too much pulling power for me to handle.
I don't care for Labs or Goldens either just because I've met so many irresponsible owners who think it's okay to not train or socialize their dog or ignore warning signs of aggression because they are a "family" breed.
I don't care for really drooling dogs either. And I can't imagine a time when anything high energy (must have long hike every day) will fit my lifestyle. And I'm not inclined towards Pugs, Bostons, Bulldogs, or French Bulldogs, between the snoring, gassiness, and looks their just not something I'm drawn towards.
Honestly though as long as I could handle the individual dogs need, if I was ever to be able to foster, I wouldn't reject a dog because of the breed.