Limericks…. must they always be humorous?

Jamuary 2014 :wisteroa by gate

I am studying poetic form.I am describing a few ideas of my interest in the next paragraph.
By choosing a limerick form I am being playful because normally I’d not choose a limerick to refer to anxiety and such emotions.And the playing itself can be therapeutic.It indicates I am like an actor on a stage having a joke with the audience.And the placement of “sure” in the last limerick is an acknowledgement that I have Celtic blood.I have kissed the Blarney stone.The Irish speak lovely English.

Do we pick a form first or the content first?

http://www.criticalreading.com/poetry.html

In general the limerick is a humorous form.That i s,both historically and by the shape and brevity.Yet I am trying to write some miserable limericks.I am finding it harder than I expected.The first one certainly has come out with more than a hint of fun

AS BROAD AS IT’S WIDE

I once had therapeutic depression

The counsellor wept through my session

So I gave my advice

As broad as it’s wise.

Depression sure beats going fishin’

OR depressed deadbeats sure love fishing

[sure here is USA]

ANXIOUS

I feel very anxious today

Would I do better to worry or to pray?

I’ll trust in the dark

in the big bush by the park.

Till a man comes along feeling gay.

I see the very nature of the form almost makes it compulsory to be funny.It’s lines 4 and 5 I think
This limerick is very naughty as “trust the darkness” is a mystical/spiritual expression… it is not related to hiding in the dark to watch for a man to come by.Even if the agent in the poem is feeling blue,the author is joking thereby.

NEW FRIEND

I hate my new friend already

I thought he would make me more steady

But I feel giddy and wild

When he charms with such guile.

Sure,doesn’t love make one feel somewhat heady