If they print out a contract with unwanted charges, then do not sign or initial it but instead circle the unwanted number, hand it back, and say, "I don't want that, take it off." If the unwanted number was machine printed, then it is better to have a new copy of the contract printed minus the unwanted number as opposed to hand writing in corrections.
Do they have a guest relations, er, customer relations department?
Some persons don't know how to hard sell and stay good natured about it but that is not my fault and not my problem. Telling short sob stories about how someone had to pay for the damages after an accident is okay IMHO.
There is no excuse for rudeness, quotas and the threat of getting fired included.
Maybe we need to start a fad of snail mailing a complaint, strictly about rudeness, including a request for a ten percent rebate, for the primary purpose of making heads upstairs roll. If that gets the agent fired sooner, that too is not my fault and not my problem although I might secretly smile if I found out.
There is one recorded instance (several years ago, Newark NJ?) of a customer reaching over the counter and wringing the neck of a (n airline) agent, but I strongly don't recommend that.
By the way, inspect the car carefully for damage before taking it out, including along the bottom edge and the entire surface of all windows and the floor carpeting.
Florida law does not require that you buy anything from the rental company not spelled out in the rental company's printed rules (policies).