Many people feel they are indispensable in their work. For those of you who truly believe this, really give some thought to what would happen if you were to leave.
Would your organization completely fail?
Would your organization falter a bit and then find a replacement?
Would your organization keep moving forward with or without you?
Would your organization improve without you?
Many of the people who think they are indispensable are more likely delusional. They might be important to an organizational but almost everyone can be replaced.
Have a great day!