Emotions can be based in reality. Or they can be based in false perceptions of reality.

That's what makes them valid or invalid.

Your fear of the boogeyman in the closet is invalid. Your fear of the drunk driver weaving around you on the highway is valid.

Of course, if you don't believe reality exists, or that reality is entirely derivation of your emotions, then yeah, you should be very very afraid and you should invest in anti-boogeyman man traps to put in your closet so he can't get you at night.

But of course, most of us would consider people who believe in boogeymen to be delusional. Delusion is a symptom of psychological problems. And delusional folks think it's everyone else who is insane for not seeing the Boogeyman.

people have lots and lots of emotions that are not based in external reality, many are based in fictions they make up in their heads. but of course, being able to recognize and admit that... is not a capability many folks develop. many folks never question their emotions at all.