Intellectualise

Dictionary dot com definition of "intellectualise"

-verb (used with object)
1. To seek or consider the rational content or form of.

4. To ignore the emotional or psychological significance of (an action, feeling, dream, etc) by an excessively intellectual or abstract explanation

-verb (used without object)
6. To talk or write intellectually; reason; philosophize; "to intellectualise about world problems"

Seeking a reality check on my understanding of this word: So, intellectualising can help a rational discussion by attempting to strip away irrational emotional responses but doing it excessively is not a good thing, yes?

So, questions I have about this are:
Are all emotions irrational?
Is there such thing as a rational emotion?
Or are all emotions irrational by definition because they cannot contribute rationally to a discussion or decision?