I love watching professional tennis on TV.
I agree as the players can get agressive at times, sending the ball in bounds without a valid return by the opponent
Yes it's very exciting and entertaining.
The players have to strategically hit the ball as to not allow an inbound return. 
I've tried to play before, it's not easy!
The tennis point system is interesting. The player unable to return the ball scores zero, the other player gets a point.
Yes and then doesn't it go to 15 then 30?
Yes ! The point system and rules of present day tennis has not changed much since the 1890s.
I guess if it works no point in changing it.
Tennis is a worldwide sport having originated in England in the late 19th century. It was called lawn tennis back then.