Prsss fit BB’s – If I can avoid them, I can. They last less time than a square taper by a considerable margin and I notice no performance improvement.
The new type 2 SRAM rear mech that I am currently using has a lot more play than my older X9 mechs ever had even after several years of use.
Avid disk brakes – I have two bikes which came fitted with them and they suffer from fade, pumping up, inconsistent performance, squeal in the wet and have had several LBS rebleeds. They simply lack the reliability that I’ve enjoyed with Shimano and even Hayes over the years so I would never buy them aftermarket.
Carbon bike frames – I wear things out. I crash. I like technical steep and rocky trails. Carbon and I are ill matched bed fellows. 😀
Internal cable routing – it looks tidy but is just another way of water getting into the frame. It solves a problem that doesn’t really exist in my mind.