Ancient - Roman/Greek - personal and domestic slavery was horribly simple, and only slightly more complex than paid servants of later years.

You didn't need to train a slave in complex protocol, because protocol was a PITA. You see slaves in images from the time, either serving or else standing unobtrusively. This was nothing that the slave couldn't be taught by other slaves.

You didn't need to brutalise a slave to teach them their place because they literally had nowhere else to go. The life of a runaway was probably worse than that of a house slave, there was a good chance of being caught, or kidnapped (iirc) and re-enslaved. And if you did find some kind of living, it wouldn't be much different and would be more precarious. (Post-roman servants were technically free, but they could still be beaten and were still trapped by the "nowhere else to go" problem.)

All that, however, is what I like about this style of D/s. It's undramatic, thrillingly bleak sometimes, quietly intimate in other times.