Tennis is like body building in the sense that you can only improve so quickly. In body building terms, you can only bulk up so fast. A body builder does thousands of reps for such incremental gains just how a tennis player must hit thousands of balls before any noticeable improvement.
Development is a long, arduous process, so you must 1) adjust your expectations accordingly and 2) take the approach of sculpting a piece of art. You can’t get a six pack overnight - everyone knows that. But if you keep chipping away at that sculpture, you’ll end up with something beautiful over time. However, if you don’t start now and put in the work to chip away at that sculpture, it doesn’t matter how much time passes. You’ll have that same ugly hunk of stone.
You always hear stories of the 3 year old who hit the ball against the wall thousands of times. It's normally a success story.
Either way it builds good discipline because it's so darn boring. It's much like playing a grinder to hits a repeatable ball that lulls you to sleep, So... you have to keep your mind engaged on what you're doing/working on because there's not much external stimulus.
Enjoy the simple pleasures of tennis like the feeling of the ball on your strings and your muscle systems working together.
Hitting against a wall, among other isolated drills, is a great way to bring the focus on your body mechanics that are often forgotten during the dynamism of a match.
If you're going to model yourself after somebody, model yourself after the best. If you're doing 80% of what Federer is doing, you'll be in pretty good shape. If you're doing 80% of most other players... well.. maybe not so much
Tennis is a game of time and energy. If you don't use energy to aggressively attack the ball with your feet to take time away from your opponent, you'll have to use more energy hitting a bigger shot to make up that time. If you do neither and hit lower quality shots, you'll be burning that energy from running around on defense. It's gotta come from somewhere.
Do the eyes sparkle...?
Or are the pupils dull and glazed over...?
In a way, it's sad to see players who don't have or lost the passion for the game and are just going through the motions, regardless of their results. The typical Tony Robbins, "success without fulfillment is the ultimate failure" applies to tennis all the same.
Speaking of pet peeves...
in doubles, when you hit a solid volley and/or multiple volleys and your partner is immobilized at the baseline watching the ball go back and forth. In theory, your partner should be using every free second to reposition.
Imagine sticking an aggressive volley and having your opponent on their heels, but allowing them to loft an easy defensive shot to your unassuming doubles partner waiting to hit a groundstroke at the baseline. Gross.
The only three things that matter: mental toughness, physical toughness, and technical perfection.
It's never one thing. Roger Federer doesn't do one thing 50% better, he does 15 things 5% better.
Don't gloss over the details.
To be a master of your craft you need to maximize all the 1%ers to separate yourself from the pack, especially as your skill level increases and the margin between players becomes smaller and smaller.