Why does urine smell so bad?

Urine can smell bad due to the presence of waste products, such as urea and ammonia, which are byproducts of protein metabolism. When urine is concentrated or allowed to sit, bacteria can break down these compounds, releasing volatile substances that produce a strong odor. Additionally, certain foods (like asparagus) and medications can also influence the smell of urine. Dehydration can further intensify the odor, as concentrated urine has a stronger scent.