This is one of the best lessons i've learned in my new life. It started with me borrowing my dads car and driving it back to him with my bike on the roof. The plan was to bike home in the nice autumn weather
It did not go as planned. The temperature dropped and it started raining/snowing. I had a shorts and a t-shirt and cotton-socks, and I had to bike about 20km, which is not that far, but poorly dressed for the occasion I can tell you it's no fun. But it was fun! After about 5km I started wondering if I would end up with gangrene in my feet. The snow/rain was hitting my face so hard I thought it was gonna freeze off.
However, when I finally got home and jumped out of the hot shower and made nice cup of tea, I felt so good!
That's when I decided to do more uncomfortable things. And here's a small LIST of things you can do too.
1. Go for ridiculous trips like the one mentioned above. Sucky weather? Go for an extra long run or bike ride.
2. Take cold showers every morning. Feels like you're dying and if you absolutely HAVE to get up, a warm nice shower sounds nice? Fuck that. Turn the shower on max cold water. Try it, and see how you feel when you get out. I promise you it's not going to feel like you suspect it will.
3. Exercise every day. Do pushups or other hurtful things every day. Sit 90 degrees to a wall until your legs collapse under you.
4. Don't eat for at 7-8 hours at least. In this age with all this "you gotta eat every friggin' 10 minutes, and eat nuts and fruits between every meal bla bla bla" what about actually trying to feel hungry? It's very natural and boy does food taste good when you're hungry!
5. Do stretches every evening and breathe into it. It hurst, but when you find that meditative state it hurts in totally new ways. Good hurt.
The idea behind all this is to not always chose the easiest path. We need to experience struggle and hardships to grow. And since our modern lives only provides struggle and stress mentally and rarely physically - you need to actively inflict it on yourself.