I've always wondered why the Olympics have (tentatively, inconsistently) disallowed professional athletes, and I find the backstory very appealing:
The English public schools of the second half of the 19th century had a major influence on many sports. The schools contributed to the rules and influenced the governing bodies of those sports out of all proportion to their size. They subscribed to the Ancient Greek and Roman belief that sport formed an important part of education, an attitude summed up in the saying: mens sana in corpore sano – a sound mind in a healthy body. In this ethos, a gentleman was one who become an all-rounder, not the best at one specific thing. Class prejudice against "trade" reinforced this attitude. Apart from class considerations there was the typically English concept of "fairness," in which practicing or training was considered as tantamount to cheating; it meant that you considered it more important to win than to take part. Those who practiced a sport professionally were considered to have an unfair advantage over those who practiced it merely as a "hobby."
I enjoy playing sports and games of all types, but I typically prefer games to sports and I've just realized that the "practice" angle is a big part of the reason. Very few people practice games to the same extent that sports are practiced, and since I don't practice either one it's just not very fun to play with people who do. I enjoy learning and experimentation, which seem more prevalent in games than in sports.
Paradoxically, I'm quite competitive and always play to win... I just like being able to have a chance at winning without having to practice in advance. Once you've practiced something and learned the narrow tactics that enable optimal play, the experimentation is over and all that's left is rigid execution of the prescribed tactic. That's no fun! A computer can execute a tactic, but only a human can create one (so far anyway).