This is one happy speaker. How can he not be? The weather is great, he's strollin' around the coolest city in the world, the wind's whipping through his hair, and he's listening to some awesome jazz. This speaker loves jazz so much, he feels as though the musicians he's listening to are his buddies. They're like his best friends, walking along with him down the street. So even though the speaker is walking around alone, he doesn't feel alone. He feels like he's got a whole gang of jazz musicians walking along with him.
Not only is the speaker happy in this poem, he feels powerful. He describes himself as "the center of the universe," "the only true point of view," and "the hub of the cosmos" (41, 42, 44). Don't we wish we felt like that? Well, the speaker feels this way because the music is making him feel good about himself. It's like when we listen to Beyoncé, and even though we may be regular folks (maybe we wear braces, maybe we're a little bit shy), we'll still feel as hot and sexy and powerful as Beyoncé.
But this is also a funny speaker. Because, even though he speaks about himself in this hyperbolic way, he ends the poem by telling us that his only goal is to get "downtown." Well, if we were the "hub of the universe," our goal would be to take over the Milky Way (and maybe some other galaxies in the universe), not just get downtown. So he blows himself up, only to make fun of himself at the end of the poem. What does the "hub of the universe" want to do? Make it a few blocks further south. That sounds like a blast…