Language is the definition of humanity. Imagine a life without any sort of communication, how do you interact with others?
How many grammar mistakes did you find in this sentence: “I am disappointment in you’re grammar”?
Who else wants to check their grammar? "Whenever i see a grammatical error, i look TO the keyboard to see if the distance OF THE letters makes IT ACCEPTABLE THE MISTAKE" Really? :)
Flesh out an idea VS flush out an idea
If you can change i.e. to in other words, and the sentence still makes sense, then you're using it correctly.