The document discusses phrases that should be avoided in one's vocabulary as they can undermine confidence and imply lack of control. These include absolute terms like "always" and "never", phrases like "I have to" that suggest being forced into things, "should" which implies guilt, "just" which makes one seem unsure, "but" for doubting decisions, and "can't" which has defeatist connotations. The document recommends replacing these phrases with more positive language that conveys personal agency, confidence in decisions, and a growth mindset.