The main problem is not being too right or too left, which in itself when it happens is indeed a problem.
I see the main problem around the globe is people being too idiotic. Blunt and simple right? People seem to takes politics like it was a football game (I mean the real football, the one with the foots and the balls, not the one with the hands and the oval, but I digress and guess that the analogy applies to any sport).
Anyway, yeah people tend to become fanatics (willingly or unwillingly, with or without realizing it) of a party, and worst of it, a single person of the party. You name it, Bush, Obama, Chavez, Stalin, Trump, Hittler, Merkel, Guaido, Bolsonaro, anyone, the end result is the same, despite the ample or few flaws they can have, the fanatics don't see them. "There's no way we can be better than right now". There's no way other party/person can further improve anything. Even "smart" people that might be fully rational regarding any other topic. People will outright ignore any faults in their own party or candidate and be oblivious to any improvement anyone else can offer, which is far more aggravating when the faults are big as a train and in plain sight. At this point some people might rethink but the real fanatics will start to make up excuses and it's all a slide down from there.
We don't need better candidates (not that we have to spare), but we definitively need better voters. In all democracies around the globe.