
Oh, when thought like that, for some it would be a hard question. But, yes, Roleplays need to have: some sort of realism, even in half-imaginary situations(that means, no Meta-Gaming->yesterday, Anto17<no offense, Anto>was metagaming from seeing some blips on a roof, but the faces of the characters weren't seen at all. Some other requirment is:
The only thing you need to roleplay is a vivid imagination

Chatscripts to avoid confusion, and other scripts are just tools to make it easier.
Another problem in server Roleplays might be some stability issues, I mean, when you crash, you have to repeat the last two things you had done before crashing to make sure you resume from where you were. It ruins the fun in having a Roleplay(which is a bit like a theater play,

) and it ruins the mood of the player, too.
Well, most scripts end up in shootings and deaths. When I got out of the car during a chase, some cops started shooting a little after 2 seconds. In character, I told them to hold on a little, that they don't want to have me on their conscience, and, that if I am resisting their arrest, they should use their self-defense weapons(electroshock weapons/Tasers or a baton), they didn't really roleplay that, but, they did stop shooting. They warned me that they would open fire when I would attempt to escape. I stalled them as much as I could by telling them that I am still thinking and so. When I decided to run to a car(which was owned and locked), all the cops started firing. So, I gave up resisting and I gave in the police. They kept shooting that car

, because I entered the passenger seat. I told them out of character that I surrendered, so they cuffed me. I asked them if they shouldn't read the Miranda rights to me. They told me "This isn't SA:MP, though!"(I was playing in IV:MP, but the server isn't that important).
So, yeah, people choose to win $$$ the fastest and go on to other stuff.Well, an important thing a Roleplay has to have is
time and
patience. A normal, true Roleplay lasts about an hour or two from my experience(a bit too long, in my opinion), so, that is why people choose to shoot fast and kill someone if he is resisting the arrest. Even hostage negotiations are getting uselessly long. I mean, yesterday, I had to repeat the conditions of the aftermath of the exchange to the police department(911 and private numbers) for more than 10 times.
Such a waste of time 
But, I kept my cool and have done the exchange, it ended up in shootings.

So, in a conclusion, Roleplays don't require much, but,
the implication behind a Roleplay makes it that "hard"(for people to be involved or try to Roleplay).