The speaker describes a day in which they keep turning into something else: a wide shoe in the morning, a committee at noon, a bus after dinner. None of these is a stable self, which is exactly what the title, "Crisis of identity," promises. The jokes are absurd, but they point at something familiar. Over a single day we play many roles, and sometimes none of them feels like us.
Each image has its own flavor. A wide shoe is something you step into, roomy and a little clumsy. A committee suggests being many voices at once, pulled in different directions. A bus carries other people and follows a route that isn't its own choice. The last line changes the tone. The bus "began to ache," and suddenly the humor gives way to tiredness, maybe loneliness. The mood starts playful and ends quietly weary, as if the speaker is worn out from being so many things for so long.