Nothing has gone wrong with the car yet.
I have changed the oil on a regular basis.
I have changed the tires and brakes.
I have upgraded the stock stereo to an after market one.
I have driven this car hard.
My commute is long and stressfull with stop and go traffic, yet the car still has not let me down.
However, the ride of the car is somewhat rough and the interior has road noise rumble, I still like to drive it.
It is lacking in bottom end power with the automatic transmission, however, it is spunky above forty miles per hour.
You're lucky -- 75K miles and not even the blown head gasket. If I were you, every 6 months, in addition to the oil change, I'd get a pressure test on the cooling system to ensure the head gasket isn't going yet, and if so, get it done before it gets more serious and expensive.
You need to get rid of this car now, while its still running. Very soon, head gasket, and transmission will need work!!!