I have quite a few passionate dislikes when it comes to modern knives -- the popular overwrought folding pry bars with cheesy tiger stripe coatings, barely functional grinds and juvenile skull motifs being at the top of the list -- but when it comes to traditional knives, I'm surprisingly open-minded.
One deal breaker for me is a poorly implemented nail nick, especially on custom slipjoints. I've seen a plethora of otherwise nice blades that were seriously compromised aesthetically by a pull that was poorly shaped or positioned, particularly when it comes to crescents.
I generally dislike imitation handle materials like faux ivory, pearl, tortoise and stagalon, etc.
If I had my druthers, shields should either be pinned or absent.
I can't abide multi-blade patterns with closed blades that protrude from the handles enough to undermine the knife's ergonomics. The popular new A.G. Russel two-blade dogleg/sowbelly trapper comes to mind, along with all too many stockman patterns.
Multi-blades dumbed-down and bulked-up from their traditional origins with the labor-saving shortcut of adding extra springs; e.g., Congress patterns with four springs rather than the usual two; three-spring "whittlers," etc.
I agree with others who've said that knives (or anything) made specifically for collectors are usually not worth collecting. This stuff is basically the Beanie Baby/Franklin Mint kitsch of the knife world. I don't mind serial numbers on solid working knives like GEC, they're too trivial to pique my ire, but I'll always choose a non-numbered knife first, all things being equal.
