In Most Stituations Don't We all only listen for personal gain?

In many different situations i find that people are only listening so that they can get something out of it. In some situtions, which are rare, people do listen because they truly want to hear and help, but in the end what you tell them can somehow cause them to be more informed. In the quote, "It's a shame that the only people who are listening to you are only interested in you because they want you and your peers to buy their product." Yes, its sounds awful, but i believe that it occurs in many other situations and at least they are asking us what we like, instead of telling us what to like. If these companies weren't even thinking of their consumers then i would be worried because people listening to each other only for some sort gain is very normal. In school, for example half the time people only listen to their teacher because they want to know what will be on the test so that they will get a good grade and then their GPA will be high. Then this high GPA will get them into college. It is very common that a student has an ulterior motive for listening to what their teacher is saying. This is very similar to parents and children. Parents and children both listen to each other so that they can form a better relationship. If they both listen then they can learn more and become closer, i know it may seem harsh, but in most situations this is true. From many different "presentation" people only listen for self gain. But this is not always true and it isn't that bad because in some situations the fact that a person would want to achieve self gain from what you are saying is a compliment.