Do your best. Always. At everything. It's hard, but more often than not, you'll feel better than if you hadn't. Even if you fail or look stupid or fall short. It's possible that the euphoria and pride of doing your best outweighs everything else. It might even motivate you to try harder next time around. And if you do that consistently, whatever limits you originally placed on the outcome could dissolve. And that's when and where magical and interesting shit can happen.
Doing your best helps curb disappointment of not reaching your goals.
Here's an idea: don't focus on your goal, focus on your effort. Change your expectation from achieving the goal to doing your best. In other words, focus on the moment and the effort going into it.
If doing your best is the expectation, then disappointment is a function of your effort. Effort is something you can control, while trying to reach a goal is a path littered with factors that are out of your control.
What's the point of not doing your best?
So let's flip the switch. What's the actual point of not doing your best? You can argue that you need to conserve your energy for something you care more about. But what if doing your best and feeling awesome energizes you instead of exhausts you? If doing your best really does drain you of energy, then what if it gives you a point of reference to try hard in the thing you actually care about? Doing your best informs you about yourself.
The most common platitude is physical fitness, like training for a marathon. One must overcome all sorts of gnarly mental and physical roadblocks in order to run a grueling 26.2 miles. In order to accomplish such a feat, you have to learn how to confront your overwhelming desire to stop running.
You use mind games to stay motivated. These mind games are portable. You can use the same games to trick yourself into pushing through mental and physical roadblocks doing the thing you care about. One mind game is probably to focus on the current effort and not worry that you've got 15 more miles to run. See what I did there?
Do you have to be self confident to do your best or does doing your best build self confidence?
When I was a kid, my dad always went out of his way to make sure I tried new things. He would urge me to try foods I'd never tasted, encourage me to come up with new ways to jump into a pool and force me to interact with adults by having me settle up the bill on behalf of my parents at restaurants. That last one is weird, but was very valuable in developing my self confidence.
I'm pretty damn self confident, although my wife sometimes likes to use a more pejorative term. My self confidence is a result of doing my best, feeling awesome about my effort and repeating the cycle consistently. Yes, it's a positive feedback loop. I'm not sure if it'll work for everyone, but I encourage you to try it. Focus on doing your best, collect your data set, then reflect and analyze.
What the eff does this have to do with your finances?
You already know what I'm going to say, don't you? Do your best. Always. At all things finance. I get that it's hard. I get that there are gigantic flaws in the way our modern world works. I get that some of us are struggling to get by because of institutional poverty, racism, social injustice, etc. I get all of that. I struggle with it too. And while we speak out and do all of the things we can to move the needle of economic justice, in tandem, we also must do our best. Even in a perfect system, no one is excused from personal responsibility.