by Seth Godin
You’re actually not teaching them a lesson, because the people who most need to learn a lesson haven’t, and won’t. What you’re actually doing is diverting yourself from your path as well as ruining your day in a quixotic quest for fairness, fairness you’re unlikely to find.
When you fire a customer and politely ask them to move on, you are withdrawing yourself from their trollish dance. When, instead, you focus on the good student, the worthwhile investor, the delighted vendor, you improve things for both of you. The sooner you get back to work (your work), the sooner you can move toward your best outcome, which is achieving what you set out to achieve in the first place.
The real tragedy of the person who dumps on you is that you pay twice. The second time is when you get bent out of shape trying to get even.
1 Peter 3:9
9 Do not repay evil with evil or insult with insult. On the contrary, repay evil with blessing, because to this you were called so that you may inherit a blessing.
17 Do not repay anyone evil for evil. Be careful to do what is right in the eyes of everyone. 18 If it is possible, as far as it depends on you, live at peace with everyone. 19 Do not take revenge, my dear friends, but leave room for God’s wrath, for it is written: “It is mine to avenge; I will repay,”[a] says the Lord. 20 On the contrary:
“If your enemy is hungry, feed him;
if he is thirsty, give him something to drink.
In doing this, you will heap burning coals on his head.”[b]
21 Do not be overcome by evil, but overcome evil with good.