We often feel frustration, dishearten and stressed when other people don't turn up to our expectations. Not expecting anything from others is unrealistic but try to at least reduce your expectations as much as you can.
All individual in this world is different and unique. No two people think the same way all the time. So all your expectations from everyone will never turn up. You might have faced situations when people took you for granted. People whom you helped a lot may have left you alone.
But relax. Life is not fair all the time. Just accept situation and move on. Find people and communities who fits around you. Spend time with people who make you smile and happy. You can't change anyone else. You can only change yourself!