Yeah, I definitely have a few.
For one, knives that can't be adjusted or taken apart down to the screws. Pinned construction means I can't tweak it like I want it, and also limits modding. It's good to see that Spyderco SEEMS to be moving away from offering pinned versions.
Serrations. Partial or full, I just don't like them. I'm a plain edge guy, mainly because that's useful for most applications and easy to sharpen. I do have one serrated blade, a Spyderco Assist, but that's a purpose-built rescue knife, so I accept that.
Co-branded knives. Bear Grylls by Gerber, HK by Benchmade, This by that, etc. etc. When I buy a knife, I buy one from a knife company. I don't want a non-knife brand or person attached to it. I don't mine a designer/collaboration name on the blade, but co-branding really puts me off. This is also a thing in the watch world, where certain brands bring out limiteds to attach themselves to a person, event or organisation. It just feels like cheap marketing.
I'll also admit to being a bit of a snob regarding country of origin, though I'll immediately admit that's also a silly thing. I just like to have my blades made in countries with a high standard of workmanship, highly skilled, well fed, happy workers, etc. Not that Chinese knives are bad per se, but… I just feel a little better paying a bit more to have it made somewhere else.