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You will be crapped upon as much as you allow yourself to be. There are plenty of jobs that are not 24/7. Especially entry level jobs, Depending on your career track, there are plenty of jobs that are higher up that are also not 24/7.
If you are answering your blackberry all night when your contract does not require you to do so, then you are poorly managing your time, burning yourself out unnecessarily, damaging your personal life, and setting unreasonable expectations for yourself, your team, and your successors.
Friends don't let friends work for free.