Until you play to 4.5 level you cannot understand the sport of tennis fully
Tennis below 4.5 is a completely different sport to tennis above 4.5. I would personally go so far as to say that 3.5 or less is not even proper tennis and 4.0 is even difficult to justify as real tennis.
Players below 4.5 just dont have the same understanding of the sport and the game. They dont know what high backhands with kick really are, or what heavy topspin really is. Attacking the net is like walsing in after a shot, these are the types of people that think approach shots at 3.5 level can be used at 5.5 level.
These are the people with an "all court" game that get beaten by a pusher who hits lob slices, these are the people who chip back a lob return and approach the net.
This is not tennis, like softball or real baseball. Tennis is not tennis until you reach at least a 4.5 level.