Issue while changing spark plugs

throw a universal joint on the spark plug socket for the plugs you cant access perfectly straight.

 

THIS. It's easy to get the extension off center and crack the porcelain.

 

It's either an illusion or just the way the picture was taken, but the one on the left, the one that appears to be cracked looks slightly different in the hex nut width and the sealing flange areas. I'd be tempted to take a caliper and try to measure them just out of curiosity.