Worst experience ever buying a car? Salesman I had...

Worst experience ever buying a car? Salesman I had was misinformed about the car that was chosen had to argue that the car hadn't been inspected. Proved that by the oil change sticker saying it had been recently serviced during its multi point inspection but the car was two quarts low. Leading me to believe someone wasn't doing their job. Could not get a price for extended warranty until I went to finance mgr the final stage only to find out then that the price of the monthly payments went up $55. Oh and people reading this understand one thing. ..the higher your APR is the bigger the check the bank or financial institution splits with the dealership so GET PRE-APPROVED BEFORE YOU GO TO THE CAR-LOT. AND ONLY FROM ONE BANK FIND THE CAR YOU WANT AND TRY TO TALK THE PRICE DOWN. DON'T ALLOW ANY DEALERSHIP TO RUN YOUR CREDIT AND DO IN-HOUSE FINANCING THEY GET A PERCENTAGE OFF JUMP AND REMEMBER THEY ALSO PROFIT FROM SALES OF THE CAR. Don't pay them twice.