Sometimes the expectations of others are not those we have for ourselves. Sometimes this causes problems if the others have expectations that we don't want to achieve for some reason. It also causes problems for us if the expectations others have don't fall in line with our dreams and expectations.
The German philosopher and writer, Wolfgang von Goethe wrote, "Man is a herd animal who does not want to be one." Always there has been the conflict in man between his wish to be an individual while at the same time there is a need for support and approval from others.
When the need for approval overrides the individual conscience, however, there can be problems. The Transcendentalists, Ralph Waldo Emerson and Henry David Thoreau wrote and spoke extensively on the importance of individualism and self-reliance. This existential condition is what makes people what they are. If a person does not follow his/her own conscience, there are always problems.
This is a matter of pure speculation and opinion, of course, so you may get a wide variety of answers. I'm not sure I really agree with your statement: I certainly don't think all the troubles we create are a direct result of "trying to meet the supposed expectations of others." While that can happen, of course, it is probably not the norm. Think of all the other ways we bring trouble on ourselves: selfishness, greed, jealousy, ambition...and the list goes on. When we do try to meet the standards set for us by others, such as high achievement in, let's say, sports, we can get ourselves in trouble by trying to cheat the system (as in the use of steroids or other performance-enhancing drugs). I'd make the case even in this example, though, that motive may have been greed or personal ambition rather than the pressure put on us by others to perform at an unreasonably high level. Interesting idea to think about, anyway.