Who told you this lie?
Some of the workers on ships of the multiple cruise I've been on who lament about the whole experience but it being the only stable work a lot of them can find.
Not to say its a blanket statement for 100% of an entire industry but there are plenty of articles out there with cruise workers telling their accounts that highlight what I'm saying.
Working anywhere from 2-8 months at a time at sea, 7-12 hours a day for 7 days a week?
Most normal mf's get stressed out at ya typical 9-5.