According to the Journal of Personality and Social Psychology, nice guys earn a significantly smaller paycheck than men of the meaner variety.

The study polled 10,000 men, asking them to rate themselves from agreeable to stubborn, and, finally, to difficult on a scale of 1 to 5. Research showed that men who considered themselves less than nice made 18% more ($9,772) on average. Variables such as education level, marital status and job responsibility were all controlled.

There are a couple of theories out there why this is the case. The first is that nice guys are more likely to brown-nose, be overly pleasing and may not bring the cold, hard honesty in a time when it’s needed for a key business decision. The other perceptions seems to be that nice people lack a bit of competence overall.

While it’s hard to prove which -- if any -- hypothesis is true, the bottom line is that it’s just another realm where nice guys finish last.