It really makes a difference in everyday life. It prevents so many arguments with my wife: we agree on most things, when we don't it's usually because we disagree on the meaning of the words we're using. At work I have far less misunderstandings with coworkers, I understand expectations better and I don't get caught out by people using vague language to hide or gloss over major problems. Last month I was evaluating a contract and it took me a week to get a clear answer about terms. I suspect the people involved subconsciously knew that if they gave a clear answer the contract would be deemed unecessary and cancelled. It was.