For example, if you want to disconnect.
Comcast: Thanks for calling in... long nonsense fill speech later... How can I help you?
You: I would like to disconnect my service effective immediately, if you waste my time and/or do anything other than disconnect me immediately, I will request a supervisor, I will accept nothing less than a supervisor, I will not allow you to put me on hold, and I will make this call miserable for the both of us until my service has been satisfactorily disconnected.
*at this point 90% of agents will just do it and take the hit on their stats to not deal with you, but if they wont, read on*
Comcast: I'm sorry to hear that sir, but I will have to transfer you to our disconnect department...
You: *cut them off* Please get your supervisor, do not put me on hold. Thank you.
Comcast: But my supervisor can't...
You:You're wasting both of our time, call your supervisor over, I'd like to speak to them immediately. Inform them that if THEY can't disconnect my service, I'll be asking for their manager as well. This will continue until my service is disconnected, I will not be put on hold.
This is way too much effort, unless you happen to enjoy yanking some chains over the phone.
Here's how you quit Comcast:
(1) Disconnect every piece of Comcast equipment in your home.
(2) Load it in a box, and put the box in your car.
(3) Drive to the nearest Comcast customer center.
(4) Dump the box on the counter and tell the rep: "I wish to terminate my service immediately."
No one will argue with you. You have completely bypassed Comcast's customer retention process by doing this. Pay the amount due on your bill, get a receipt with a complete list of the equipment you've turned in, then go home.