If you have read any self-help books, you have undoubtedly read the adage “Nice guys finish last”. Now research from Notre Dame and Cornell Universities show how being too agreeable negatively impacts your earnings. 

More recent research from Stanford, Northwestern and Carnegie Mellon) continued on the same path showing that people who are overly caring, for overs, generally tend to make bad leaders. In particular, being overly nice generally means that you will likely fail in 2 important leadership domains: prestige and dominance. Prestige comes from sharing within their group while withholding gave the person dominance. 

The researchers said:

We predicted that contribution behavior would have opposite effects on two forms of status – prestige and dominance – depending on its consequences for the self, in-group and out-group members. When  the only way to benefit in-group members was by harming out-group members (Study 1),  contributions increased prestige and decreased dominance compared to free-riding. Adding the  option to benefit in-group members without harming out-group members (Study 2) decreased the  prestige and increased the perceived dominance of those who chose to benefit in-group members via intergroup competition. Finally, sharing resources with both in-group and out-group members decreased perceptions of both prestige and dominance compared to sharing them with  in-group members only (Study 3). Prestige and dominance differentially mediated the effects of contribution behavior on leader election, exclusion from the group, and choices of a group  representative for an intergroup competition.

Their research showed that in situations of group competition, individuals preferred having a dominant leader over a prestigious one (since the prestigious individuals were perceived as more submissive). So nice guys (the ones that share) are seem as prestigious and thus nor thought worthy of leadership during trying competitive times.

You can therefore assume that when things are going great and no major competition or risk is felt, people then prefer a prestigious boss.