Expectations – Buddhism believes that they are the cause of great suffering. The expectation that your friends will always remain your friends, that they will be loyal to you, that the feeling of companionship will remain to the same extent over time. That the people you love will love you back.
We are only human, so we love the status quo. And can live within it for an infinite amount of time. But life is a great teacher, untiringly and consistently teaching us what we need to know. And life shows that us that nothing remains. Eventually, you do lose your friends, loved ones, the image you have of your body, and lastly your memories. Everything that makes you the person you are. And only then do expectations cease to be.