Athenian democracy was subject to bouts of mob rule - note the treasurer incidents. Courts were barbaric, and really amounted to popularity votes as jurors had little legal oversight. At the assembly level, for their credit, the criteria for citizenship required military training and voting for war generally meant you had to actually do the fighting - hence the level of peace.

Mobs form when there is no responsibility for their vote or actions. That's why in unrestrained democracies, the mob majority can disenfranchise the minority so easily and quickly.