Putting on a front at work may not be such a bad idea, according to psychologists.
Honesty is often said to be the best policy in social situations.
But while this may be true at home, it does not necessarily follow in the workplace, say researchers.
Scientists assessed levels of "authentic self expression" in 533 volunteers to see how far they opened up to people they interacted with socially.
The results showed that participants were more likely to "be themselves" with partners, followed by friends and then parents. However, they were much less likely to show their true self to work colleagues.
Those who showed their true selves to partners tended to have greater well-being and were more satisfied with life. But the same benefits were not seen from being authentic at work.
Dr Oliver Robinson, from the University of Greenwich in London, said: "You hear self-help gurus say that the secret of happiness is 'being yourself' or 'expressing your true feelings', but that doesn't seem to apply in the workplace - at least for the sample we studied.
"So in some circumstances, it may be that a polite smile or tactfully keeping quiet may be more conducive to your well-being than saying what you actually think and feel to work colleagues."
The results were presented at the annual meeting of the British Psychological Society, taking place in London.