There are two thing I would like to say.
One, it seems that a lot of people seem to be forgetting about the "Sleeping Mode"-Feature for Nikos phone. If you are annoyed by your friends, turn on that mode and they'll leave you alone until you deactivate the mode again, and you won't even lose any of their fondness.
The other thing is that I'd like to add that San Andreas was full of Myths (Bigfoot, Leatherface, the Wheel Chair, ...). I don't know about you guys, but me and my friends had a blast searching for the serial killer, trying to find Bigfoot, and desperately trying to survive in Area 69 long enough to find some UFO, not to mention the thrills we got when hearing random screaming voices or seeing things in our imagination.
GTA IV on the other hand had way fewer Myths, the most famous ones being Ratman, the Heart of Liberty City (Which is actually an Easteregg, not a Myth), Lola of the River, and the Ghost of Playboy X and the Sprunk Factory.