I think a lot of people say they believe their jobs are disposable/replaceable but in reality they are thinking "My job is disposable/replaceable if it wasn't m

I think a lot of people say they believe their jobs are disposable/replaceable but in reality they are thinking "My job is disposable/replaceable if it wasn't me doing it. I make it indispensable!" That's one problem and corporations use it to their advantage. I have been in the position a few unfortunate times where I had to let some people go. Some for cause, many due to downsizing. It never ceases to surprise me when people say something along the lines of "but how could you do this to me? I work so hard. You need me!" and they believe it. Heck, even now as I say this I can think of times where I thought exactly the same way about myself and my job. But, it was never the case.