Right. "There is one thing or the other, nothing else" is always an illusion.

Pay attention to your thoughts.

If there is an overall theme to thoughts (like "fuck everyone" or "I suck") then there is likely an underlying emotionally charged event feeding them all. Deep introspection can expose and help release that event, causing the "related" thoughts to become weak and not arise nearly as often.

Grabbing or pushing away thoughts are habits, and both actions reinforce those thoughts to arise again. Often people will grab at thoughts that bring them pleasure and push away thoughts that bring them discomfort, then check out into fantasizing when all seems neutral.

The more one indulges in anger, the more anger one craves and the more likely one will habitually jump into anger without forethought. The more one rejects certain life realities, the more one will dwell in fantasy and become at odds with reality, needing fantasy (or junk food or drugs) to cope with consequences of their disconnect.

Note there is a ton of nuance: every person has different triggers and hangups, so I'm just speaking generally here.