Watch a video of lips mouthing “ga” while the soundtrack says “ba”: most people hear “da”. This is the McGurk effect, described in 1976. Your brain fuses what it sees with what it hears, and the image can override the sound. Most unsettling of all: knowing it's an illusion doesn't make it go away.
Every day, your kidneys filter around 180 liters of blood plasma, about a bathtub's worth. Yet you only have about 3 liters of plasma, so it passes through your kidneys some sixty times a day. Over 99% of the filtered water is reabsorbed, leaving just one to two liters of urine.
A 70 kg adult is made of about 7 × 10²⁷ atoms, or seven billion billion billion. The observable universe is thought to hold on the order of 10²² to 10²⁴ stars. Even with the high estimate, you contain thousands of times more atoms than there are stars in the entire visible cosmos.