This is beautifully illustrated in judo class. Sometimes you are the tori (person demonstrating a technique). And sometimes you are the uke (person on whom a technique is demonstrated).
Your experience and growth as a judoka will directly relate to how you perform these roles. If you want to master a technique as the tori, you need an uke who will work with you, someone who will take their falls and gradually increase their resistance as you perfect your technique. In return, a good tori will protect his/her uke, making sure that their fall is not too intense so that the performance is repeatable. And then you get the opportunity to switch roles and give and take with your partner as they just gave to/took from you.
It's a fine life lesson as well as a way to succeed in the dojo. When you give of yourself, no matter how scary the fall my look, you open yourself to a plentiful return.