Three turtles got me thinking

Three turtles decided to have a cup of coffee。 Just as they got into the cafe， it started to rain。
　　The biggest turtle said to the smallest one， " Go home and get the umbrella。"
　　The little turtle replied， "I will， if you dont drink my offee。"
　　"We wont，" the other two promised。
　　Two years later the big turtle said to the middle turtle， "Well， I guess he isnt ing back， so we might as well drink his coffee。"
　　Just then a voice called from outside the door， "If you do， I wont go。"
This joke makes me feel that there will be no progress without trust when friends start a business together.