Nobody remembers that your fighter had teh 18 strngths.
Everyone remembers when they vaulted over the coffins to kick the magic macguffin out of the hands of the bad guy.
But at many tables, what your STR stat is makes a difference to the likelihood of success if you declare, as your action "I vault over the coffins to kick the magic MacGuffin out of the hands of the bad guy!"
If mechanical resolution matters to anything that is important, then the inputs into that resolution - eg PC stats - aren't of no relevance at all.
Back in the 4e RPGA heyday, my friend and I played a pair of dwarven brothers. I played a melee ranger, he a maul fighter. They were a lot of fun to play. We went out of our way to inject a lot of quirky personality and roleplaying interactions into the sessions. Often people would ask if we were going to play our dwarves because they enjoyed having them along. I don't think they really cared all that much about our particular classes or roles so much as wanting to participate in the memorable moments we'd strive to create in game.
Some people are fun to have along to a card night even if they're not very good game players, because they're fun people to hang out with.
RPGing puts a distinctive twist on that, because part of the game involves (or, at least, can involve) creating a fun person for others to hang out with.
Now if you're the person at the card night who is really serious about
the game, then you might get irritated by the nice guy who keeps missing tricks when you're partnered with him. If you're the person at the D&D session who is really serious about beating the dungeon, then you might get irritated by the player whose PC is fun and memorable, but who keeps triggering all the traps.
I don't think there's anything
wrong with being that serious person - though you might want to tone it down in more light-hearted company. But it's certainly not the only way to approach playing a game - and in D&D it's complicated by the fact that for some players the fun personality is a higher priority
for the game than beating the dungeon. (Some people seem to go so far as to say that aiming to beat the dungeon is actually a
wrong way to approach D&D. I don't agree with that either.)
EDIT: I saw this reply:
It seems like the proper correlation with your analogy is if I were to fail to bring my character sheet, dice and a pencil. But that's not what you are implying, is it?
How about this to turn your analogy around: Let's say I show up to play that team sport with you. And I *do* bring my shorts and runners. But I'm not quite as good at the sport as you--yet we are having fun playing--I guess you'd still be upset? Even if I bring my "A game" and roleplay the heck out of a really interesting and fun character, that happens to be less optimized than yours--yet we all had fun playing--we still have a problem?
I think I've already answered this above, but will say a bit more.
If I joined your soccer game, having told you that I can play soccer, I can almost
guarantee that you would be irritated by me - because my soccer is terrible. (I can do the running bit, but not any of the ball control bits.) The fact that I told funny jokes all through the game might somewhat mitigate the irritation, but - at least for many sports players - actually playing the game is part of the point.
In D&D it's more complicated because not everyone agrees on what the point is. Not everyone agrees that "beating the dungeon" is the point. But clearly for some players it is, and they're not obviously wrong.
And as I posted in post 77 a little bit further along in the thread, a further factor in D&D is that
overcoming challenges is a definite thing. Whereas there are other FRPGs (eg BW) which are superficially similar to D&D, but in which
confronting challenges rather than necessarily overcoming them is the core of play.
As I say in that post, I think it tells us something about D&D that someone who is
criticising optimisation nevertheless identifies Rufus the 6 STR fighter with no armour, who wields a club one-handed, and who hates fighting, as a non-viable character.