Meaning?
(1) You have to be able to smile ...
Americans sometimes use "got to" for "have got to" or "have to" . :)
(2) For some reason the person must listen to, or in some way survive during some questionable things. They are suggesting that you have to be able to smile during this.
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Be as happy as possible, during challenging times?
While your boss talks nonsense, smile if you don't want to be fired?