I don't think it was a mistake but because your luck didn't come at that time, you thought it was because of your mistake. But in particular, accidentally clicking the bet max button is your fault. Maybe because you were in a hurry or thinking of something else, you didn't double check everything and pressed the button right away. For that one, I also often experience it in slot games and I intend to choose a small bet but in reality, I instead choose a bigger bet and lose. Well, we just have to be careful when playing gambling and always ensure everything is in order before we press the button.
I also have a same experience, but luckily I double of my money because of my mistake, after that I stop to gamble and cash out my winning to enjoy my day. But most of the times I keep losing and that's has been expected because of house edge. Gambling for long surely will make your money lose and almost has no chance to make money, while bet in bigger amount has a chance to make money.
Both are game of luck, the difference might be the gambler's way of betting but along the way the outcome are mostly the same, you'll lose your money if luck is not with you, like what you said, house edge is part of the advantage from the casino after that you will need to handle your emotions and that's affecting most of the time, greed and aggressiveness two things that hard to control when you are involved with gambling, though there are experienced gamblers who can manage part of it but not every time, chances that they also exceed and be moved by their emotion still possible to happen.
There are incidents that they also experienced that same mistake. Instead of letting that mistake, they tried to cover it as they are being pushed by that adrenaline and the outcome is not in their favor.