Yesterday, I got a necro-comment from Magson on my very first EQ2 post, back when I was having trouble finding the "sell" function on NPC's.
At the time, I blamed the game's "hail" command (which gives you all of the separate options for an NPC, such as buying, selling, starting quests, etc), but the more likely culprit is that not all EQ2 vendor NPC's will actually buy all of your junk. Most likely, I hailed one NPC and was given separate options to buy or sell stuff, and later decided that a different NPC wasn't buying my stuff because I had hailed him to buy instead of sell.
Nowadays, I don't hail things at all. There's an option in the user interface for "double click to perform 'default action'" (with an exception for when the "default action" is to attack the target). Clicking this on most functional NPC's will bring up their vendor UI without the need to select it from a menu.
There are two minor quirks to this approach. First, doubleclicking a quest giver who also happens to sell stuff will open the vendor UI in addition to starting a conversation with them about their quest. Not a huge deal, you just have to close the vendor window to see what the NPC is saying. The other issues is that the "default action" if you double click on a piece of player-made furniture is to "examine" the furniture. The worksmanship that went into the carpet sitting behind our guild hall broker is fascinating, but what I really wanted was to talk to the broker instead of opening a description window that I have to click on to close (pushing escape also closes the broker window that I actually WANTED open).
Sounds like a bit of an annoyance, right? Well, a bit over four months into my stay in Norrath, it turns out that I still don't know the basics of the user interface. Magson pointed out that the F key can also be used for "default action". If, instead of attempting to double click the broker at the risk of missing and examining the countertop, I mouse over the broker until the icon changes and then and push F, I'm very unlikely to miss, and thus everything works perfectly. (That said, if there's an option for "double click for default action when the default action is neither attack target nor examine furniture", I'd be happy to hear about it.)
Learning the ropes
The fact is, learning the basics of an MMORPG is pretty hard. I remember having a conversation with Riannon relatively early on in my EQ2 career to the effect of "I'm moving very slowly instead of running, and it's not because I pushed either the "X" or the "C" key, what wrong key did I press?" (Sadly, I don't remember what the answer was, so, for all I know, I'm going to need to ask again sometime.)
If you're lucky, people will bail you out when you warp into an unexpectedly hostile star system or whatever, but, for the most part, we learn by doing. It's usually possible to figure out how things work to some minimal level in order to play the game, but you won't try things that don't occur to you. For example, I have no idea what would prompt someone to think "F" for "default action". Perhaps it's merely close to the traditional WASD movement keys, I don't know. For that matter, I've hit level 61 in EQ2 without ever playing in a group, which could be a problem if I ever try to attempt it.
Then again, it's not exactly as if throwing a massive manual at the player before they've even tried the game is going to help them learn. There's a reason why Free Realms' user interface accessibility gets so much praise - you actually don't need to read a book to figure out how it works. Meanwhile, a more demanding game is going to require more options and more commands, so going with extremely simple isn't always going to be an option.
In conclusion, hard user interface design is hard.