good point @nalufei
Strange because the Quests Completed achievements appear to go up to 2000
There are Achievements listed for completing Random Quests also, going from 20 all the way up to 50,000
From the achievement descriptions 'Completed X quests' and 'Completed Y Random Quests' one could assume that the random ones refer to the daily quests, and also that reputation quests should count.
I guess that we should also remember that the original mythos had a slightly different random quest system [I don't think it was daily, perhaps someone like Bobcat could confirm]
Perhaps the counters are configured differently in this version or something.
Would be nice if someone could confirm one way or the other