I played in this man's PBEM game from the very day it began. It started out as a lot of fun. Then we got into his main plot, and he started with the railroading and blatant favoritism toward his two friends' PCs.
The GM kept promising that everyone would get their chance in the spotlight. I tried to be patient with him, and suffered through feeling like an extra in The Amazing Adventures of [His Friends' PCs], because I thought he actually meant what he said.
I was wrong. Not only did he give his buddies' PCs the Kewl Toyz (TM) and make them the prophesied saviors of his world (while the rest of us got diddly squat), but he allowed them to steamroll over the rest of us with impunity. And when my character complained IC, he told me to act more like a team player. Excuse me? Why would my PC want to listen to a pair of people who dismissed his every idea simply because it wasn't one of theirs, and denigrated his accomplishments on a regular basis?
Then my husband started playing in the game (with the approval of the GM) and I started to have fun again as the two of us played out a little romantic subplot. Given that Mr. GM had allowed his friends' PCs to spend an afternoon shopping and chatting with each other, and let one of them tell the requisite Tragic Story From Her Past, and then posted it on the mailing list, I thought, "Hey, why not? I don't think he'll mind...after all, he let [his friends' PCs] get away with pretty much the same thing..." Wrong again! The GM threw a hissy fit because my husband and I both happened to be playing guys, and they got a little frisky off-list. Never mind that it happened in a private interlude, and he'd put absolutely nothing in the rules about that sort of thing being taboo, he had to have a verbatim transcript of what went on, and then blew a gasket because we "weren't supposed to be doing that!"
It got worse. The GM's main plot involved the characters having to save four mystical towns from the Forces of Evil. Each time we were sent to one of the towns, our characters were instructed to go and meet with the local All-Wise NPC, and then we would return to find the town under attack by the bad guys. After this happened twice in-game (and one of the PCs was prevented from saving the ruler of the second town because the GM hadn't planned for that happening - "No, [PC's name]! You and your companions go on through the dimensional rift to the next town - I'll be all right!" Um, you'll be "all right," when your realm is being overrun by the forces of darkness even as you speak? Obviously, your definition of "all right" is different than ours....), we decided to split the party when we reached the third town, leaving half of the PCs behind to defend the town while the other half consulted with the local All-Wise NPC. No soap. We were told, "Oh, we'll be fine! You should all go off and meet with [the local All-Wise NPC]!" After some fruitless arguing, we did as we were told, only to return and find the town being overrun by the forces of darkness again, and be told again to go on to the next town.
Then came the infamous Character XP survey. Perhaps I'm missing something, but when you ask "What don't you like about this game?", you ought to be prepared to hear honest answers. When this GM got them from the hubby, he proceeded to chew him out via e-mail and then went behind my husband's back to me in an attempt to get me to tell the hubby he "ought" to rethink his answers. And don't even get me started about the "Tell me what you think about each of the PCs in the game and each of their players; I'll be forwarding those opinions to each of the other players" question. That was a recipe for disaster, as one player's "honest answers" were another's "insulting and hurtful remarks." Between the fallout from the survey, and generally being fed up with this GM's iron control, my husband and I quit the game.
Apparently, though, that wasn't the extent of the GM's railroading. Later, I found out that the reason the PCs kept trying and failing to save the various locations they went to was because he was going to give them a Time Machine. Yes, a Time Machine. Can we say, "Deus ex Machina?" I could sort of understand if this was a desperate attempt to fix things after the PCs had royally screwed up, but he apparently had this planned from the very beginning (given his previous behavior, my husband and I figure he couldn't have come up with it on the fly.).
There is a postscript to this story - after we left this game, my husband and I imported our PCs to my tabletop game. As a nice gesture to some of the other players in the PBEM game, I sent an update on what our characters were doing in my game to the mailing list. The GM sent me a rather didactic e-mail telling me how I "ought" to be running things in my own game ("Well, what you did was so-so, but I would have done it this way...."). Apparently, he's quite convinced that he knows what's best for everyone, even those people who aren't in his game.