From the point of view of someone who has been a captain (often of several teams per season) for almost 20 years, a few observations:
Except from those who have been captains themselves, there aren't many pats on the back for being a captain.
Most players do, however, appreciate a captain they perceive as fair and knowledgeable (and having a winning phhilosophy).
Most players, even given the opportunity, don't want to captain a team. I had a mx. dbls. team that went to State a couple of years in a row and had good chemistry but when I had to step down as captain the following season, the team disbanded because no one would take the captain's job.
Because I have been a captain I think I am more understanding and less outwardly critical when I play for another captain but I also do my share of second-guessing him/her (to myself!).
Finally, I am sure there are a number of motivations for being a captain but I have seen two or three significant categories of captain over the years. There is the captain who takes the job to be certain he/she plays more than would be true if just a player. Then there is the control freak captain who has to be in charge. And there is the "I have to make everybody happy" captain who makes sure everybody plays the same amount as much as possible even if it means that he/she sits out most of the time and the best players may be out of the line up for the big match at the end of the season.
But when all is said and done, let's hear it for all the captains out there!!