Callaway Irons and anything else that is too thick and looks like a shovel. I don't like too much offset either.
I was gaming these ^^ (steel shafted) up to last week. Retired them when I got my hands on a brand new SLDR set for $500. Would have preferred the JPX-850f but they are a bit out of price atm with the baby coming soon.
I've been thinking that the look of the club doesn't matter for way too long. As others said, there is too much good clubs out there to endure ugliness.
I used to feel the same way, then I started putting with one and I couldn't care less. I've been using it for about 4 months now and the other day rolled some blade style putters at Dicks, man I just can't go back. The stability and consistency far outweighs the bulky look.
I have to like (not love) how a club looks to game it long term, that's just the way it is for me.
There are way too many good looking options out there for every spot in the bag for me to have some ugly clubs in there.
I like blade putters. I bought an Odyssey fang becuase of all the good things I heard about about mallet style putters. I tried it over a couple of rounds but really didn't like how it felt and I always thought it was ugly. To each their own.
I don't have a threshold, if something fits me like a glove then I'd love to play it. I have preferences with appearance but if a club looks good then its just a bonus for me.
The only things I don't like are huge busy mallet putters and lots of offset in irons.
Beauty is in the eye of the beholder. I liked the Cobra irons in the original post.
To me, anything that lowers the score is beautiful. Heck, I play Altitudes and Niblicks. Do you think I care what other people think about what is in my bag?
If anything it just serves to spark conversation. I've probably sold more Cleveland Niblicks for Cleveland than half of their reps did.