What i mean is, what class is your priority to kill? or a class you know you will die from if you dont take care of fast. My usual priority is Medics. Especially if their UberCharge is ready. let it be Quick-Fix, Kritz, or Stock, Medic is my First. i Fear Medic the most because (almost) one Uber changes the whole battle. The medic is Feared and Loved.
Edit-Funny most people say Pyro. i Main pyro. hehehehehehe.....watch out. i may burn your beds and pizza when your not looking >:D