I never said anything about what will cause you to have more or less fun.
This sort of response is a fully general counterpoint to any claims that there are more or less correct ways to play. "Ah, but what if instead of attacking the monster, I want to jump off the nearest bridge? What if that's more fun for me???"
Well, I guess you should go and do that, then. What am I going to say to that? "Don't have fun"? "You're having fun wrong"?
This is fine until you play group games. (Like WoW or D&D.) In such games, the goals of the group are usually aligned with the goals that form the core of the game system.
In WoW, almost all challenging group activities involve killing monsters. If you're bad at killing monsters (or tanking monsters, or healing people who are being hit by monsters), then you are bad at contributing to group success. If the group is not successful, the group members will not optimally have fun. This is true in at least 95% of cases.
D&D is similar, though with a broader focus. (We can have a whole discussion on what the core goals of D&D are, but the gist is the same: the game system focuses on certain goals; being good at contributing to the achievement of those goals is critical to group success.)
My advice on optimal play assumes that you want to be good at accomplishing the goals that the game places before you. If you don't, then the advice obviously does not apply to you. (You wouldn't object to a "How To Wash Your Car" guide by protesting that you like your car being dirty, would you?)
Finally, there's a crucial difference between deliberately choosing this or that play style, and just being bad at the thing you are trying to do. Nornagest's comment elaborates on this.
This is fine until you play group games. (Like WoW or D&D.) In such games, the goals of the group are usually aligned with the goals that form the core of the game system.
I don't know what kind of groups you play with, but in my groups, the closest thing to a common goal people can agree on is, "let's eat barbecue for dinner", and even that is sometimes iffy.
Your posts on this topic sound perilously close to saying, "everyone who doesn't enjoy playing exactly in the same way I do is wrong", which is a mistake, because your optimization strategy does not apply to an agent with different goals.
There are things that are worthless-- that provide no value. There are also things that are worse than worthless-- things that provide negative value. I have found that people sometimes confuse the latter for the former, which can carry potentially dire consequences.
One simple example of this is in fencing. I once fenced with an opponent who put a bit of an unnecessary twirl on his blade when recovering from each parry. After our bout, one of the spectators pointed out that there wasn't any point to the twirls and that my opponent would improve by simply not doing them anymore. My opponent claimed that, even if the twirls were unnecessary, at worst they were merely an aesthetic preference that was useless but not actually harmful.
However, the observer explained that any unnecessary movement is harmful in fencing, because it spends time and energy that could be put to better use-- even if that use is just recovering a split second faster! [1]
During our bout, I indeed scored at least one touch because my opponent's twirling recovery was slower than a less flashy standard movement. That touch could well be the difference between victory and defeat; in a real sword fight, it could be the difference between life and death.
This isn't, of course, to say that everything unnecessary is damaging. There are many things that we can simply be indifferent towards. If I am about to go and fence a bout, the color of the shirt that I wear under my jacket is of no concern to me-- but if I had spent significant time before the bout debating over what shirt to wear instead of training, it would become a damaging detail rather than a meaningless one.
In other words, the real damage is dealt when something is not only unnecessary, but consumes resources that could instead be used for productive tasks. We see this relatively easily when it comes to matters of money, but when it comes to wastes of time and effort, many fail to make the inductive leap.
[1] Miyamoto Musashi agrees: