Careful with Hiding your Success and Being Modest
Being modest about your achievements or successes may seem like a nice trait to most people, depending on the culture perhaps.
But Roberts et al. found from 8 experiments, in both public and private settings, and for both family, business and romantic relationships, that modesty can actually backfire on you, because although those who hide their achievements are perceived as more modest than those who shared it, they are also seen as less competent and less warm!
See Johari Window
for one possible explanation of this phenomenon.
Individuals often hide their successes from others but that such hiding has relational costs. Apparently people who receive such communications by a successful person can feel envious (jealous) and happy for the other person's success at the same time. "Sharing one's accomplishments with others is superior to hiding for maintaining one's relationships."
Note that all of the studies were conducted in the United States. People from the US clearly have a more positive attitude towards "selling your achievements" than Europeans or Asian people do.
Source: Roberts A.R., Levine E.E. and Sezer O., "Hiding Success", Journal of Personality and Social Psychology, 120(5), 1261–1286.