A common mistake that most men make is to button all the the buttons on their suit. This certainly is one of the No- No’s of mens fashion and should be avoided to save themselves the embarrassment of making a fashion blunder.
With a two button suit, the bottom button is always left unbutton. A suit should be buttoned at all times when standing and unbuttoned when sitting. In the case of a three buttoned suit, the bottom button is left undone, with the middle button always buttoned along with the first button.
There are times when the first button is left unbutton because of the roll of the lapel. Remember, the bottom button is always to be left unbutton.