Good friends give you constructive advice, encourage you, and still love you though knowing all your shortcomings. They are not always around, but will definitely show up when you need help. They are delighted by your success and happiness; they care about your worries and pains. They push you up.
Bad friends speak guileful words and pretend to like you but may betray you under certain circumstances. During your good days, they would like surround you and flatter you; when you lose your wealth and status, they vanish quickly. They gloat at your loss and misery. They may lack self-discipline or have bad habits, which exert bad influence on you. They drag you down.
One takes the color of one’s company; one receives moral influence by close association. So, we have to be careful of what kind of friends we have and be proactive to choose the right kind and avoid the wrong kind. The famous talk show hostess Oprah Winfrey ever claimed some friends could be toxic and would ruin your life, whom you would rather be alone than hang out with.
Taiwanese writer Yu Guangzhong - I guess he is a leisurely man - ever classified friends into four kinds: classy and interesting, classy and boring, vulgar and funny, vulgar and boring, which sound a categorization of people.
We can choose our friends; meantime, we are chosen by others. We should be good human beings and beneficial friends first to deserve good friendship.