it is not like a job where you have a guaranteed salary at the end of the month.
This is quite possibly the biggest misunderstanding people bring here... there are nop guarantees, and you're not "employed" by Steemit, and the site doesn't "owe" you anything.
All you have here is an opportunity and it's up to you to make the most of it. If you want guaranteed income, go flip burgers....
Yeah, sometimes people act like they have a right to a nice payout because they worked hard on their post (especially the new Steemians) and they are confused why other people are getting high payouts on posts they regard to be of lesser quality than theirs. I myself am glad at the opportunity and am having a great time on the platform.