I think you need to be careful sometimes.... pointing out someone who is worse off *can* have the effect of negating the original person's feelings.
There is always someone who is worse off, that's true, but it doesn't mean the things that are bugging you are not important. :-)
Your priorities in life are set by your experiences, and everyone is so different.
It is a good thing to focus on the happy things in life, that's true, but don't feel guilty about the things that bug you. :-)