Rather, it's the avoidance of unhappy emotions and thoughts that create distortions, leading to neurotic emotional and mental patterns. These emotions and thoughts will arise on their own regardless of how you try to suppress them (and often times, suppressing them will make them grow stronger).
The basic practice is very simple at it's core: what arises will arises, what passes will pass. So when it arises, you allow it to arise -- and remain aware. When it passes, you let it go -- and remain aware.
As things that have normally been suppressed start surfacing up, it's as if you are "sweating out" these toxic thoughts. It will get worse before it gets better.
It goes deeper than that, since detoxifying isn't the ultimate aim either. It's the direct experience that what you think of as "self" is really an illusion. It's only after that, that things start get really interesting.