Huh? Why? I've done nothing but love it the day I bought it...

Got her a transmission that works properly, had EGR issues fixed, the coolant leak into my UIM fixed, new tires, breaks/calipers/rotors all around, new master cylinder, wheel bearings L/R front....and most recently (today) a new Cat (the UIM leak toasted it w/ the constant misfires ) and also fixed another coolant leak (those two infamous pipes) around the lower. I've done all this over the course of less than a year, the car has never gone more than 2 months without the engine light coming on for some reason or another...But today, I dunno....After picking it up from the shop only to have it half the day before the f'n light comes back on just kills me. I haven't even owned it a full year and I know any sane or normal person would have gone back to the dealer and traded it for something else. But my car holds sentimental value (it was bought for me by my ex) and it's also a car I've wanted for a while and had been searching for. I've no clue what the new code is after getting the new cat today....If it turns out to be an o2 sensor I'm gonna be pissed...Too late to find out now, we'll see tomorrow. I keep joking that by the time I'm done my car will have been unwillingly rebuilt, I'm beginning to think that might come true at this rate. Oh, and I wont get into the ABS/Trac Control issues that worsened after the new tranny was installed. Which in itself I'm beginning to think might be the cause to my ABS/Trac issues. My mechanic noticed a couple tranny bolts missing and under certain conditions (going up a curved road ) while accelerating the front end seems to stumble a little, something I assumed was alignment related. Now I'm beginning to think it was a sloppy tranny install....if that's possible....The ***** is, the car has low miles 104k now (88k) when I bought it, it's super clean and in almost mint condition. It runs and drives perfectly when it's behaving. And it's a Anniversary Edition GT with matching trim, not like all the other dime a dozen GP's around town. I dunno...I'm running out of money and patience...I just needed to vent a little too feel better about being a super stubborn chick...