I've never had a problem with updates in 7 years of Macs, but I always see people here or on other sites complaining that they have. As it's the same updates & operating system for everyone it makes me wonder what they've been doing.
I've never seen this on a Mac, I have seen it on a Dell though. The cable frayed and sparked on my girlfriends old Dell laptop power supply. I didn't sue though because it was wear from her picking it up by the cable repeatedly for 2 years.