Reciprocity$-$ People feel obliged to provide discounts or concessions to others if they receive favors from those same persons. In this story, the salesperson recommended the tractor which has a discount. Then mentioned about $5-$year warranty and fee. That fee John has to pay in two years. By understanding that John is not expecting this then mentioned a $1-$year warranty and the fee.

Scarcity$-$It is a perception that products are good and attractive when availability is scarce. In this story, the salesperson mentioned this particular model is so popular which is on sale that weekend and everything was sold out, and only one available is a bigger size also, the salesman explained if he is in the place of John he will definitely buy the last tractor before another customer comes

Authority$-$There is a tendency to obey authority figures, consider as an expert in the area to offer good decisions in a short time. In this story, the salesperson explained about all models with different specifications and then he asked John about his lawn, then after a few calculations salesperson recommended a model

Commitment$/$ Consistency$-$Human being has a deep need to be seen as consistent. Once people establish a commitment, they continue in the transaction. In this story, the salesperson explained about all models with different specifications and then he asked John about his lawn, then after a few calculations salesperson recommended a model. And offered a discount. That model was listed as best buy in a leading consumer magazine. Thousand of satisfied customers purchased it$.$ Sales man established consistency in this model and John became continue in the transaction. The salesperson recommended taking the warranty. Then mentioned about $5-$year warranty and fee. That fee John has to pay in two years. By understanding that John is not expecting this then mentioned a $1-$year warranty and the fee.

Liking$-$ People like those who like them or act as friends. In this story, the salesperson initially connects with John by asking about his family, children, and hobbies, and he seemed more interested in John and seemed similar to john. That model was listed as best buy in a leading consumer magazine. Thousand of satisfied customers purchased it$.$ That indicated that that model is popular and used by many people. People like the goods when others use it$.$

Social proof $-$People do what they observe other people doing. They rely on other people on how to think, feel and act, believe similar to others. In this story, the salesperson mentioned a particular model of lawn tractor for John which was on sale that weekend but all were sold out. That model was listed as best buy in a leading consumer magazine. Thousand of satisfied customers purchased it$.$ That indicated that that model is popular and used by many people. This principle is influential among people to buy.