I've had many minor problems.
My car: 2001 325ci steptronic with 21k miles, bought new.
The biggest was the passenger door handle broke 3 times. The infamous HK rattles. My steering wheel down volume button would change the radio station or cd track, they replaced head unit. Popping noises from rear speakers (replaced the amp several times) but started after they replaced head unit. Now they gave me a amp that absolutely produces nill in bass, I have bass and treb on max now and my HK sounds like stock

(. Control arms where a huge one. Control arms are expensive. They first replaced bushings which only slightly helped and I had complained 4 times about steering noises to get control arms replaced and guess what NOW I have no problems. I've had my sunroof track greased several times from noise (normal maintenance). I'm sure this helps prevent most track problems that people are having where the sunroof falls off of it. I've had all but one of my turn signal lights fail two failed twice. My front brakes have been replaced twice and rotors once. The rear have been replaced once. This seems excessive to me with only 20K miles. I can't see spending $300-500 every 10k miles on brakes when the warranty is up!
My center air duct still makes weird howling noises from time to time. The newest thing since I have a steptronic is my shifter is getting stuck. I had trouble getting past neutral just this morning. All weekend I had trouble moving from sport to manual mode. I've had other questions more than problems which service treated as problems and gave me a hard time about when really I was simply asking whether something was normal or not.
I have had two nails in my sidewalls of my tires which caused me to replace them. The stock tires wear really fast so I've spent $800 just in tires. This is why I have no mods! Overall I'm spending about $450 per year in maintenance on a new car! I actually need two front tires now that's another $400 plus I need winter tires this year, that's another $600+! arrrrrgghhhhh! This will bring my total to about $800 per year in maintenance since 2001 granted I had two flat unrepairable tires before. Also I change my own oil in between service intervals.