When we think about political systems in most western democracies, we can take a bird's eye view that generalizes two political entities. The Left and the Right. While of course this is a very broad concept, these differences are also perceived by most mainstream journalists and the man on the street. It seems that a mono-directional scale is the most the majority can suffer, more detail would only pose problems of sorts.
So, let's take these two sides for granted and leave complicated elements like Libertarians out of it. So why do we who are not in the middle but outside of this spectrum so worried about the actual center of it.
Well, you could say it does mean that after a time both sides have been in power. Some years it was the left (Democrats, SPD/Greens etc.) and sometimes it was the right (Republicans, CDU etc.).
The two sides have very fundamentally different views on life. Both on the elite level see themselves as superior and wise. They both believe the rabble has no idea about the right way to live and govern. How I can come to such a straightforward conclusion? Just think about it.
The Left believes that the poor and downtrodden are victims, some are victims of the evil right, some are victims of themselves, because they are deluded or stupid. In every case, they have to be helped and encouraged to do the right thing. This means that the state has to create services that help them (e.g. give money to them), but also to nudge them in the right direction (Food Stamps rather than pure money).
The right on the other hand has also a negative view of the poor and downtrodden, however, they also believe they are malicious and devious. They believe that those moochers will take every opportunity to ransack the social services, if they are not surveilled and guided by a strong paternalistic state.
Now I leave it up to you what will happen after several power changes in a state and a certain smoothing and averaging. You will have the worst of both sides. The surveillance state of the Right and the paternalistic tendencies of the Left.
This is what modern democracies in the western worlds work towards. It is what in most cases we already have in China. A really brave new world, imo.