The only thing bad I can remember is about 4-5 years ago I was home late from work and desperate to build my new HTPC rig. I was in such a rush, I slipped with a screw driver and put a tiny scratch on the side of the outside of the case where the fan was being installed.
Luckilly when the HTPC was in position you couldn't see the scratch. I still have that case in its original box in my loft
I had lots of fun and games removing/installing socket A heatsinks but never did any damage to the hardware, my finger nails on the other hand...