Ohh I remembered one
-Free-To-Play: Don't get me wrong, the feature itself isn't the issue... I like the idea that I don't need to pay 15 dollars a month to enjoy a game (even if my current favorite MMO is subscription... but dang do I wish I had friends in it). So when I heard I could play MMOs without paying through the nose I jumped in on that. Now while they were VERY grindy at first that wasn't the issue at first. The issue was later on these MMOs started to show their true colors in that they are incessantly naggy as they constantly and ceaselessly try to get you to put real money into it. Some of them do it by constantly flooding the game with pay moments or by making certain aspects of the game nearly unbearable without it. Neverwinter for example does both, you will find "money only" locked chests as well as a crafting system that is nearly unbearable if you don't put cash.
I know a lot of people put down people who are against the free-to-play model... but dear goodness I cannot stand it when I pick up an item and it basically tells me "ohh by the way, you need to pay real money if you want to actually have this item"
Puzzle pirates is by far the best model for free to play I've ever seen.
Every (large) purchase requires a cost in both coins and doubloons. Coins you get by just grinding or participating in the (95% player run) economy. Doubloons you get by paying cash. HOWEVER, there is an exchange where you can trade coins for doubloons as an open market amongst players. Thus, anything and everything can be done in game without ever paying a red cent, if you're good enough. Which is quite possible, because success in the game depends entirely on actual player skill, since every mechanic is a pretty well made puzzle that you can as a player be good or bad at. As well as being real life savvy on the player run economy or not. They also have poker, and puzzle tournaments, and a fairly intense social game in the form of organizing hundreds of people to take over islands and then getting rent from business owners, etc. etc.
But yeah, basically free to play if you're smart and skilled at puzzles (hardcoded or social ones). And not free to play if you are too bad at the game to sustain yourself. Yet the company is guaranteed that the most efficient percentages of the population are both, because doubloons MUST be sunk per purchase, and somebody MUST pay for them so there must always be a group of people buying doubloons, and there's always going to be some group of good enough players to exchange for them instead (how good you have to be to be self sustaining depends on your appetites).
Due to the puzzles, it's infinitely better than Eve online, because if you're a skilled actual player, you can theoretically start a brand new character, not interact with anybody, and be the captain of a frigate with 400 people on it and kick everyone's ass within, like, 5 hours or something. One time I actually did become a captain (including the few requisite experience levels they ask for + winning enough for the doubloon fees) and actually recruited like 10 people from the docks and was sailing in a used ship in 12 hours, without saying a word about who I was to anybody / not relying on any connections. There are extraordinarily few hard restrictions on anything based on your character. Basically just a sort of short mandatory tutorial / alt abuse sort of filter period of a few hours.
I also played that MMO several times a week for about 3 years in college and paid a grand total of 2 months' worth of typical subscription costs the entire time, because that's how long it took me to pick up the skills needed to ride along for free. I suspect most DF players would be smarter than average enough to do so as well, honestly. You don't have to be like top 1% or anything. Probably more like top 25%