Low self esteem,risk taking,socioeconomic status and smoking by parents. Pick one of these of your choice. I recommend socioeconomic and risk taking since it is very common nowadays.
Farce is further identified by exaggeration and absurdity, two other elements in Chekhov's one-act play. As a farce, then, "The Proposal," or "The Marriage Proposal" as it is often translated, sets a tone of absurdity with such elements as slapstick.