Going downhill fast

One butterfly spies
A glint in his eye
The birds sing
As he cycles by
Oh, why should he feel sad
This world ain't so bad
And besides
Woe betide he who would frown
When natural beauty abounds
And now, with wheels spinning free
He's picking up speed

Two butterflies
Tie knots in his stomach
They love it when he goes too fast
The wind whistles past
Vast
Oceans of air
That will mess up his hair
Though he no longer cares
Anymore for
Over-indulgence in vanities
Vacuous vice
Just once or twice
Thrice
Four times in five
We forget we're alive
And neglect to remind ourselves Wait,wait for me
Oh great Mercury
As late as you may be
Will you wait for me?

Three butterflies realize
When it's time to depart
They have tickled his ribs
They have fluttered his heart
But the starting is easy
Compared to the stop
And the bottom is hard
When compared to the top