First of all, "Transitions" is a brand of photochromic (darken when exposed to UV) lenses, made by Transitions Optical, a subsidiary of PPG (formerly "Pittsburgh Paint and Glass"). There are a number of others, including those using lenses made by Corning.
Buyer's Guide to Photochromic Lenses, Variable Tint Lenses, and Tinted Eyeglass Lenses at AllAboutVision.com
I believe that people who don't like this type of eyewear don't have real Transitions -- they have something else. Real Transitions are fantastic IMHO (I have no connection with them or the optical industry whatsoever). No tint indoors, excellent performance when outdoors. The best. So: know what you are buying. Insist on seeing the certificate that comes with real Transition lenses, or the optician's invoice, etc.
The "riding in cars" thing is also complex. Higher-end cars have excellent UV shielding in their glass anyway, which is why there is no glare and Transitions work fine to drive with (even though they do not darken). "Driving lenses" are a thing of the past. All front windshields, and side windows in better cars block UV ... and therefore glare. You can test this with photochromic glasses ... I check the side windows this way when buying cars.
I found the forum where lens professionals hang out like we do here ... and there is an engineer from Transitions making this very point:
Light through the car's side windows allowing Transition lenses to darken. - OptiBoard Discussion Forums