I hate self-checkout. They put more people out of work and the self lanes always take much longer. IMO I avoid them whenever possible because I'm ornery. The real checkers appreciate it as well...
I hope that is sarcasm. If anything, it keeps people with 2 or 3 items out of long lines, where they tend to be grumpy. In all of the stores I have seen self checkouts in, the same number of people are checking, but with shorter lines.