I think that depending on the age of the child, a little potch is ok. BUT, this is if and only if you regularly shower your kids with love.
A child who truly knows they are loved, will grow and blossom regardless of whether they are hit (of course, not abusively and only until an appropriate age), yelled at, criticized, or punished.
Whereas, if a child does not feel loved, any form of discipline (which children always see as negative) can have a disastrous effect.