It's also just creating players who are perpetually upset. They want the game to match their expectations and thus be able to say "I'm playing by RAW"... but get unnecessarily bent out of shape when WotC won't design the game in the way they want it.Honestly i think it’s kind of detrimental to the best potential DnD experience people can have that there is such an emphasis on ‘playing exactly by the books’ rather than making their own things, not to say everyone should be making up rules or content or doing whatever they just want to do arbitrarily just because they can, but just things like you said, just creating a custom spell list to fit a character concept rather than trying to awkwardly cobble together bits and pieces from classes and feats all over the place that never really end up fitting together how you really wanted them to.
For me it's always been simple-- if I don't care how something plays, I'll just use what WotC has given me in the rulebooks. It's easy, it's written down, and my players have easy reference to it. But if I DO care how something plays (and the rules as written don't give me what I want) I will adjust said rules myself so that I can play the game how I prefer right from the start.
Other people, however, seem to just want to sit and stew in their own anger, waiting/expecting for WotC to eventually get around to making the changes they want. And I'll never understand those people.