When I worked in traffic safety, a critical point was that systems need to be forgiving. A momentary lapse in attention or judgment should not lead to disaster. Granted, we live in the kind of universe where that’s just the way it is, but your design should seek to minimize that rather than to wrap people around trees.
In terms of game design, I am thinking about UI rather than combat here. Most games have figured out that one-click character deletion is a Bad Thing. Most games let you lock items or bags so that you cannot accidentally sell or deconstruct an important set of gear. Another aspect is that these need to be sufficiently customizable: if there are too many “click OK to confirm” screens, you start automatically clicking OK without thinking, which is just a more tedious version of not having the warning. As a player, I want to be able to pick what is hidden, what gets a warning pop-up, etc.
In terms of hardware design, I need a computer case whose power/reset buttons have a panel over them. I want it to be like the self-destruct button you’d see in a movie, with the clear plastic cover you need to flip before hitting the big red button. I’m not worried about myself in this case. I have a cat.