I experience server-side lag on Diablo 3 on a regular basis. I know the difference between lag caused by my end, lag from their end, or lag from a computer; each type of lag is different. It’s extremely rare to even go for an afternoon session without encountering lag. I’ve got 300mbps internet with 10-40ms ping, and I don’t experience lag on most other games that I play. If it was my internet, then I would lag on all of them. I don’t usually experience horrible lag, but a few seconds of lag is all it takes to lose a character, and I get that kind of lag often enough to be worried about it. No, I’m not one of those people who just freaks out and blames their death on lag every time they die.
Do you really not believe in lag? Have you been that fortunate? Gaming in your shoes sounds amazing.