My Own Little World

[i.might.be.a.bit.sad]

Unless you describe more about the world the speaker was in in his head, i might change the title. Just an idea.

I spoke to a blind man on a bench in the park today.
He asked me to describe what was happening around us.

I had just walked about the park for fifteen minutes with nothing on my mind<-- this phrase is so rich with opportunity to put in a great word, and you choose "nothing". Try to be more poetic. "dullness" or a color or something. Just something to think about.
but the bleakness of my job and relationships, and the hopelessness of my ambitions.

I hadn’t noticed the ducklings in the stream following their mother,
or the family sitting on a flannel blanket (comma maybe?) delighted by their presence.
I didn’t hear the busker pluck his chords and sing “hallelujah”
while more leaves than coins fell into his guitar case. <-- love the juxtaposition between hallelujah and the leaves in his case. Happiness in bad times. Beautiful.
I never saw the dog chase after its frisbee, unable to catch it in the air,
pounce upon it on the ground.
I hadn’t seen the teenagers partially hidden in an enclave of trees
sit in a circle, passing around a paper smile, laughing at the wind.

I never thought to look.

I really like this, but i might change the title as i said, and maybe describe your interaction with the blind man more at the end. What did you say to him?