These kind of jokes were the memes of the previous generation
Discomfort is widely available anywhere you look, you simply need to know how to capitalize on it. We are so accustomed to comfort as a convention that we begin to forget just how easily we can revert to being uncomfortable. When it is a cold day, we instinctively dress warmly to avoid discomfort. When it is a hot day, we dress cooly. When we know we are to walk long distances, we wear comfortable shoes. On occasions where we will be away from long, we eat large meals before starting out, so that we won't be hungry. Etc etc. Once we recognize these habits, we in turn recognize opportunities to become uncomfortable, and in turn, to PRACTICE discomfort.
We can elect to be hungry! We can elect to be cold! We can elect to be uncomfortable! These are all sensations freely available for us to choose to experience. We need not be forced into enduring these situations; we can choose to. And in making the decision to choose discomfort, we put ourselves in the position to practice being comfortable BEING uncomfortable. All that needs to occur is that initial decision to CHOOSE discomfort over comfort, and once that is made, the process begins.
Your results may vary
These can be minor decisions and actions initially. If it's winter, and it's below zero with windchill, instead of breaking out the parka, just go with a jacket. If it's summer and 100 degrees with 100% humidity, go with the t-shirt and jeans instead of tanktop and shorts. Take a cool shower in the morning instead of a hot one. Start practicing discomfort, and start making it a habit. And, like all habits, eventually you will find yourself choosing discomfort OVER comfort when given the choice.
You build a tolerance to discomfort eventually, which allows you the opportunity to practice even greater degrees of discomfort. You will eventually find yourself seeking out opportunities to be discomfort. I get excited about cold winter days, because it gives me a chance to go practice being uncomfortable that I would not on a more milder days. You learn how to wear only t-shirts in the winter, how to take cold showers, how to live in and with pain, and in doing so, you make it so that, when you encounter discomfort OUTSIDE of your choosing, it does not phase you. The more frequently you practice discomfort, the more easily you deal with it, because it is YOUR norm.
Clearly this person is no longer uncomfortable looking stupid in the gym
And THIS is what we train for people. We train so that, when we experience discomfort, we DON'T shut down. You can spot those who are uncomfortable being uncomfortable vs those who aren't. The latter are the ones that are chugging along top speed in a medley only to hit one snag and completely quit. The latter are those who stop lifting as soon as they hit a single plateau. The latter are those who shut it down as soon as they experience the slightest hint of pain during training. Put simply; they are the ones who DON'T succeed. They can have all the physical talents and gifts in the world, but because they refuse to experience discomfort, they never allow themselves to really get pushed to the point of greatness. They ease off the throttle JUST when the real work starts to occur. They leave the spoils behind for those who have gotten uncomfortable being uncomfortable through consistent practice.
Practice discomfort UNTIL you are comfortable being uncomfortable.