I actually think that this repeated message that they are the happiest people on earth makes individual jws feel that there is something wrong with them if they are not happy... just one more thing to live up to... it's telling them that if they are living up to all they are supposed to do and pleasing Jehovah then of course they are happy. If not...something is wrong with them. So they try harder and are still miserable... It's a viscous cycle.
Coffee