If Moody : Reliability, then?
Extemporaneous : Predictability.
Unreliable : Inhuman.
Tenacious : Practicality.
Heated : Boiling.
A moody person cannot be reliable. Similarly, a tenacious person[the one who is not readily relinquishing a position, principle, or course of action, very stubborn type, determined] cannot be practical.
FYI, Extemporaneous is an adjective. It means: done, spoken, performed, etc., without special advance preparation; impromptu. Like someone giving a speech without preparation. It is usually a one time act, not a nature of a person.