Interestingly, with all our perceptions about death and "haunted" graveyards, I'm told that there are few spirits in such places. Aside from the guardians we've mentioned, and perhaps a few others, the bodies in graveyards are just that - bodies in peaceful repose. The souls have gone elsewhere, as a rule.
In the logic of the living, we think that because the bodies are there, the graveyard must surely be chock full of agonized, wandering spirits. As it turns out, it seems the opposite is more the rule.