I am trying to not be too negative, but come on people.
Lol. No explanation is necessary...bad players make it harder on the GM. When even a single player fails, that makes it harder for the GM to maintain momentum.
I, for one, think GMs are way too lenient with bad/rude players. In all truths, a good PbP GM is worth 20 players. And if a GM has a player that isn't pulling his RP weight, they should be quick to try to resolve the issue quickly/quietly (a personal message usually works) and, if that fails, find another player.
GMs don't have to put with bad players within Paizo PbP...there are many more players than good GMs. A GM should be able to find people who fit his playstyle and run an awesome game.
Let's look at this from the GM side. What makes PbP harder than in real life?
- No immediate feedback. When there is a problem or a mistake, it can take hours/days to find and fix.
- A GM cannot read facial expression of players. Hugely important. Some things are easier in person. But it's easier to identify points of confusion in real life.
- Not knowing when to push, pacing is harder. This is the single hardest thing for a new GM to figure out. It's hard to know when to let RP flow and when to push sagging action. A GM will occasionally 'herd cats' to get the party back on task...it happens in every group.
- Online map work. This is another issue: figuring out how to give strong and fair mapped combats. Sure, Rolld20, Googledocs, pic hosting all work, but what best fits your skillset? Which one are you trained in and feel comfortable with? It's a bigger issue than you think.
- Having to read and respond to everything. A real life GM (usually) gets questions one at a time and can focus and prioritize how and what to answer. In PbP, it requires reading every post and seeing each post for what needs to be responded to. Kydeem touches on it above: it's very frustrating as a player to have to ask the same question post after post. It's easy for a GM to miss things in PbP that normally wouldn't be missed in face2face.
- Difficulty in describing your story/action/environment. Hand gestures, intonation, inflection all matter in communication...but are much more difficult in PbP. A map with two or three dimensions is a lot of PbP work...a clarification on a map might be two quick pen strokes to fix and explain in real life, but take a lot of map time to fix in PbP. In PbP, you need to be able to explain story and setting via the written word. That can be much harder in PbP for some people (some people are not strong writers, or English is not their first language). Some people are better storytellers via the spoken word.
- Focus. The good DM must be more focused than the players, more on top of the game, more energetic - everyday for years. If the DM falters, the whole game falters - much more severely than when a single player drifts for a bit.
I'm sure there are more reasons why GMing is harder in PbP, but the real point is that, as a player, you need to help make the GM's job easier by being clear about what you are doing and being responsible for timely posting.