The M in ATM stands for machine, so there's really no use in saying ATM machine 'cause then it would just be redundant, amirite?

I hate it when people do this. It's like saying SIN number or PIN number.

What does the T stand for??

OP watched episode of sarah silverman :)

It actually stands for automatic teller machine, so if you said machine after it, you would be called it an automatic teller machine machine.