The Perfect Metaphor for Life
The major insight about life is that nothing is easy. Easy is earned. And weight lifting is the perfect metaphor for life. In fitness we have a principle called SAID (specific adaptation to imposed demand). In other words, your body adapts to the way you train it. Well, so does your psyche.
Just like with weight training, in life you must continually challenge yourself with progressing difficulty to get better and grow. Your muscles respond only to new challenge. Same with your mindset. With each new challenge there's growth, and this incremental growth begins to snowball like compound interest.
Build a Resilient Mindset
Most people simply won't do it. They've never trained to have a resilient mindset. We are all inherently fearful, lazy, and ignorant. Some might see that as depressing. I find it inspiring. To me it's the secret to success.
All I have to do is be a little less lazy, a little less fearful, and a little more willing to question my assumptions and biases. Then I can achieve amazing things. And the weight room is my testing ground. A new PR in the gym helps me prepare for new fear PRs in life.
Your brain is always watching you and judging the type of person you are. When it sees you attacking the gym consistently day after day, month after month, it's more likely to believe you and support you when you attack something new in life.