If you're talking about cheating on a partner, then it's a horrible thing to do that they will remember forever. It will mentally destroy them and force you to destroy everything that you have built in your relationship. You guys hate each other and are now total strangers, never to be together again.
If you're talking about cheating in videogames, I think it's fine as long as you don't impact other people's gameplay experience. Like if you're using cheats to progress faster or to grind better, I think that's perfectly reasonable.