Political revenge mainly, but that can manifest itself in many forms. I'm not a psychic. I just know that Political revenge can range anywhere from light oppression to state endorsed violence. It will be different depending on the country and their own unique situations. It really all depends on how much the left will struggle to force the political pendulum further left before it's momentum brings it back to the right.
Politically society moves left-to-right and right-to-left over time and stays within the parameters of a common middle ground - that's the pendulum. The real problem is that the left has gone to such extreme lengths and has pulled that pendulum far left by forcing their will on the rest of society though various institutions, lobby groups, and executive fiat. The last 10 years have been quite undemocratic where the citizens haven't had much say in terms of policy making unless you belong to a "special group."
The pendulum is going to come back the other way and with much more momentum than it would have under normal circumstances, swinging it further right. That is unless countries manage to elect moderates, or center-right leaders, but looking at what is happening in some European countries and the kinds of protests they have having that doesn't look all that likely in a lot of cases. Then you throw war, or major economic problems (which is also a possibility) into the mix and you get a much worse situation.