Bigsby. They look stupid, weigh a ton, are worse than a Floyd to restring, and you can't do all the cool obnoxious Floyd stuff.
Glossy maple necks and especially fingerboards. That crap sticks to my skin like glue, looks awful, and feels like I'm playing a plastic guitar.
Neck dive. Probably the biggest deal breaker.
Anything that feels heavy. Unintentionally, all the guitars I have now are pretty light. My LTD M1000 and Tele are both a little over 8lbs, the rest are low 7s, and one of my Carvins is like 6.5. Even my Les Paul is well under 8. My current line up is the best bunch I've ever had, and while I'm reluctant to attribute that to the weight, it's unlikely I'd ever buy anything much over 8 lbs again.
Vintage specs, like tight radii, stupid tiny frets, PAF-style pickups, crap like that. If you dig it, cool. I don't.
Piezo pickups. Yuck.