Seriousness is important.

Everyone needs to be serious to be reasonable! Who could live being light hearted and careless? 

-Lawyer McNitie, Jury in New Jersey Court

First, I would like to say being serious can have a serious reason. For example, a serious man or woman might be so serious because their job is to be serious. That's a lawyer for you all right!

-Sir Arthur IX of Rome

Well seriousness is important.

-Mrs. Seer E. Us

To conclude this, being serious is important, as said by these seriously important people.

-The Serious Society