OK, Olivia, I will respond. I didn't start playing until relatively late, when I was college age. Took a few group lessons but nothing serious. Played some recreational tennis, mainly on a ladder system. My biggest "win," if you can call it that, was when I was in law school, I took a set from a guy who claimed to have played on a team in college. (He never played with me again, by the way!) This was over 30 years ago, now, but I can remember it like yesterday.
These days, I don't play that often and hardly ever play sets or points, just for exercise and to knock the ball around. I am a huge fan of the sport, however, always watch the Grand Slams on TV, for about five years we had a group of about four of us who for several years picked players for the big tournaments on a point system, winner gets a free lunch, etc. I always try to get to one or two tournaments in the US in person, this year I went to two days of the tournament in Key Biscayne and hope to go for at least one day in the summer tour stop nearest me, which is Washington DC.
Comparing today to when I first started following tennis, one thing I kind of regret is how, except for the GS and Masters level events, you rarely see all the top players on tour at one tournament stop these days, although I understand the reasons why -- the points system, avoiding injuries and being "overtennised." I still remember sitting in the hot sun for the first pro tournament I ever attended, in DC back in 1971, for a $4 admission got to see Laver, Emerson, Newcombe and Stan Smith (versus a young Harold Solomon) on center court in the first round action; in those days, I didn't wander around to the side courts like I do today. (Had I done so, I would have seen guys like Rosewall and Ashe up close and personal). This year, I would be willing to guess you will be lucky to see two top 10 players at the DC tournament, although a few years back I remember seeing a great match on a side court between two South American guys who subsequently reached the top 10 and a GS final (Fernando Gonzalez and Guillermo Coria -- Coria won).
My favorite players have changed over the years. For the men, it was originally Newcombe, then Vilas, then Edberg, then Pat Rafter (who I first saw at Newport back in 1993 when he was an unheard of 19-year old ranked something like 266 in the World). Current favorite player is Fernando Gonzalez, who seems to play with a level of passion and instensity that I feel is missing in many players who look like "robots" on the court. No strong women's favorite, although I have been a big Elena Dementieva fan since I saw her at the US Open some 11-12 years ago now when she was just 17 or 18. Side comment: It's amazing that someone with probably the worst serve I have ever seen can have been ranked in the top 10 for a decade now!! One young player I haven't seen in person yet but who I was really impressed with a couple of years ago when I first saw her on TV is Michelle Larcher de Brito of Portugal (when she was part of the WTT Championship team at 14). Saw she took a set off Serena last year, but has recently been struggling now that she isn't getting the WCs when she was a junior phenom.
Back to answer your question, why I like tennis, I think because it's the ultimate one-on-one competitive sport without the violence of say, boxing. Right now, it is one of the four sports I care the most about (the others being cycling, soccer and figure skating).
Hope this is what you were looking for, and I would be interested in reading more responses to your post, as I feel too much of the commentary on this forum is relatively narrow, specific and not really demonstrating a true passion for the sport, although I do have to admit that I enjoy hearing from this brent kilray character now and then.