I mean, it's a great way to bugger up your neck - watching the ball swing left to right and back again.
Well, one needn't watch the ball. Maria Sharapova is retired, but she was entertaining to watch from behind. I'm sure there's something for every preference.
The game can also be played, you know. But it's pretty difficult to play at even a consistently decent level. It's also a bit of a psychological game, as I suppose most individual sports are: one can attempt to deceive one's opponent while remaining entirely within the rules. Vide Renoir
Règle du jeu.
However, one has the opportunity to try to hit a less skilled opponent with a ball of great speed, which is entirely legal, unlike in pool or snooker.
For example. a classic exercise in tennis is to set a visible marker, like a plastic cone, and try to serve to that exact spot. Dozens of times, repeating that. Accuracy is very important. Now imagine your opponent's head or torso as that target. Not very difficult, if one has strong wrists and good aim.
Hustle to the net and aim for the gut or melon with a two-handed backhand or strong forehand. Won't work with a baseline game.
It's bad form, but so is setting up to serve a good Roddick-style ace and dropping the ball just over the net when you're serving.
I think gin rummy is the only card game that approaches that kind of flexibility, and straight pool (or maybe eight-ball). Pro-tip: if you're ever in a fight in a pool hall, don't use the cues as weapons. Word is, courtesy of Danny McGoorty, grab a handful of balls off the table and break somebody's teeth out.
No, I've never been in a bar room brawl over pool, but that's the word on the street.
I'm disappointed when I see most top-tiered name players today at tennis just staying at the baseline. Serve and volley is the better tactic. ***, I see people of ages 60-70+ on the courts staying at the baseline: it's like watching old people ***. The hustle to the net is the good tactic.