Yes, and what do you think I meant? Meeting people on the street, striking up conversations about D&D in general, and then lecturing them about how they are Doing It Wrong?
Less sarcastic reply:
While individual DMs and gaming groups may, of course, deviate from common practice to such an extent that what is outright detrimental in most groups is actually a direct path to victory in that particular group, such large deviations are relatively rare, in my experience.
In any case, by "play effectively" I of course meant "play effectively, given the circumstances". But some advice can be pretty general, such that "the circumstances" are so broad as to be almost any circumstances. For instance:
If you are a 10th level wizard, is it effective to take feats like Far Shot, Weapon Focus (crossbow), etc., and spend your actions in combat shooting at enemies with a crossbow?
No. It is not. Your performance will be sub-optimal in no less than three ways:
You will be much less effective, will contribute less in combat, than your other party members (assuming that they are not similarly crippling their effectiveness). This will make your party mates feel that you're deadweight, and will make you feel useless.
You will be much less effective than a wizard who specialized in proper wizard things, like casting spells. You will even be much less effective than a wizard who specialized in shooting things with a crossbow... and then cast spells anyway.
You will be much worse at shooting things with a crossbow than a fighter who specialized in crossbows. You will even be much less effective than a fighter who didn't specialize in crossbows, and then used crossbows anyway.
Is it possible to contrive some convoluted scenario, some bizarre set of "house rules", DM-specific practices, and other quirks, that conspire to make the crossbow-wielding wizard optimal in any of the above ways? I suppose it might be. You'd have to work pretty hard at it.
The fact is, if someone says "being a wizard and shooting things with my crossbow is how I like to play; there's nothing wrong with it, so don't criticize me", 99% of the time they are, in fact, making the manifestly and grossly sub-optimal choice. Unless their DM has imposed some hilariously twisted set of house rules by means of which that choice becomes optimal, the problem is almost certainly that they simply do not understand how D&D works — so basic a concept as some classes being more suited to some combat techniques than others, for instance.
P.S. Responses of the form "now I am tempted to build an effective crossbow-specced wizard", while amusing, do not constitute a rebuttal of my points. ;)
While D&D evolved from a strategy boardgame, it is still a role-playing game. As such, it includes storytelling elements, which, depending on your GM and the players' desires, may weigh far more heavily than monster-slaying.
Some GMs prefer to run their games as a straightforward dungeon crawl: encounter enemies, kill them, repeat. In this case, the optimal character would be the one who is maximally effective at slaying monsters, or supporting fellow party members who do so.
Other GMs introduce logical puzzles into the mix. In this case, while your cha...
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: