Replacing the shocks on my 17 year old car.
The rears came off easy, but on the right front the lower shock bolt had rusted into one piece with the shock. After applying significant force, I was able to get to a point where the bolt and the metal sleeve around it would just rotate in the rubber bushing. I tried whacking it out with a BFH with no luck. I ended up having to use an angle grinder to cut the eye at the bottom from the rest of the shock, and then cut through the whole eyelet and bolt twice so I could slip it out.
Now the garage smells terrible because I punctured the shock body and some oil leaked out.
That was yesterday, I haven't worked up the courage to touch the left front yet...
Almost every time I try to work on something on this car that was exposed to the elements, there's something that's extremely unhappy to be removed from whatever it's had time to rust into. I swear I soaked every bolt with PB-blaster the day before. I even soaked them with PB-blaster a couple months ago in anticipation of doing the shocks now. It helps but not enough.