I can always tell when someone is riding their horse in a tom thumb bit. It's usually the horse with his head straight in the air and with his mouth open and jerking his head to any kind of pressure from the reins.
I'm a believer in the saying that bits are only as harsh as the hands that use them, but you can tell when someone designed a bit made for people who don't know how to have soft hands. Take for instance, the bicycle chain bit:
The Stop n Turn bit:
I don't even know what this bit is called:
For those of you who hate TTB, how do you like THEM shanks???