Why is it poetic when they have plenty of those German sandals in the store? Because they're Birkenstock.
Poetic German Sandals
Explanation
Explain Bear
Listen up, buttercup. This joke is all about wordplay. "Birkenstock" sounds like "Birkenstock," which is like saying someone or something is poetic. Get it? No? I'm not surprised. You probably think a balanced breakfast is a donut in each hand.