Shout out to those are under appreciated

Do you ever feel under appreciated? Do you ever feel someone is taking advantage of you? Gosh ... everyone is feeling that... why is there any appreciation manner in human circle nowadays. I just learn today, no matter how hard you work for a company it is easy for them to just script you out because in their mind YOU are easy to be replaced.
What happen to appreciate the effort? I hate this ... Stand up ... just stand up and get out of the situation ..