Most mistakes in gambling happens because gamblers gambles so many times in a week, they get attached to gambling like it's daily job, what OP said about making mistakes when you stay away from gambling is wrong, you make less mistakes when you are not too attached to gambling.

The casinos even want gamblers to get so attached to gambling, this is one sure way they gamblers will keep coming back, and they will make more money this way.

If you are a smart gambler you must not get used to gambling, have fun gambling but don't expect money flow from gambling, you are just sitting on a time bomb, when the time is up you will likely lose everything or get addicted.