Choice of words
Words are a powerful tool. I'm sure many have heard the saying that the tongue is the most powerful weapon. Should one say " You do this" instead of "Let's do this", the former gives a very authoritative and dictatorship feeling which may not be welcomed by many while the latter gives a more supportive and encouraging feeling.
Saying things such as " I completely understand how you feel" may cause one to lack credibility in the eyes of another as no one can really understand the other person completely.
Asking "Why" can come off as being too interrogative. Instead, alternative questions could be like " What do you think can be improved" which may come off as more positive and in a lighter tone.
Phrasing and choice of words are important as saying the wrong things may offend people or cause one to lose one's credibility.
One should think before one speaks