Here's a context
There’s a habit we all do in everyday life, one that is called rumination. To ruminate means to chew over. It's when your boss yells at you, or your professor makes you feel stupid in class, or you have big fight with a friend and you just can't stop replaying the scene in your head for days, sometimes for weeks on end. Ruminating about upsetting events in this way can easily become a habit, one that is very costly. Because by spending so much time focused on upsetting and negative thoughts, you are actually putting yourself at significant risk for developing depression, alcoholism, eating disorders. You really need to stop thinking
And for the purpose of fully understanding how to use 'one' that is used to add an idea after the sentence finished, I've made two usage. Am I right to use this way?