Playing within our means

Why is it so hard to play with in our means? Actually, why is it so hard to live within our means? Is this human nature? I know almost everyone can relate to what I am saying here. How many times have you wanted to turn $100 into $1,000, $10,000, or $1,000,000? Its possible that you even got off to a decent start before taking a few steps back, and/or going broke making poor decisions? What stops us from being rational? Why not just realize that to get what we want we will need to work very hard, put in lots of volume, use proper bankroll management, fade the ups and downs of variance, and try not to play outside our means.
I am going to give an example. I have a friend who has been running pretty well for the last year and half. He cashed in several big tournaments and recently got his first win and a six figure payday. He just arrived in vegas and had a plan for most of his tournaments but right after showing up gets a hard on for the 25k at Bellagio,  sells some action with no mark-up, and hops right in. I am not saying he is necessarily doing anything wrong but it just seems human nature to play to the absolute limit of our means. He is a good player but he is a $300-$2k buy-in tournament player, I am not sure he is ready for crushing 25k buy-ins. It just made me realize that the 1/2 player that wins $300 off his one and only $200 barrel and then signs up for the $500 tournament is not far from the tournament regular that gets a win and then hops in the biggest buy-in event he can find.
What will it take to keep us satisfied with crushing a level within our means instead of rising through the levels so fast it can get risky? Is it just a realization and then some effort or is it more than that? I think a true understanding of variance and BRM could go a long ways but might not stop you from wanting to quickly rise through the levels. But, if you could do it in small steps maybe the risk could be decreased.
I think once a person starts winning and doing really well they can almost get brainwashed with the upside of variance and it usually takes some brutal loss to bring us back to reality. How many players do you think go through these things? I would be willing to bet most players battle these things. I bet even the ones that are really good at doing these things right, still have to make sure not to slip, because slipping is very easy.
Sometimes I just like to rant a little about the things going on in my mind. I suppose right now I am wanting to build my bankroll up, but want to make sure I do not get ahead of myself so I can give myself the best chance to get what I want. I hope everyone is doing well, improving, and controlling all their emotions while they grind. Good luck all!