No. In spite of our differing body sizes, most of us have very similarly-sized internal organs. So if you need to pee faster than your friend, it's probably not because your bladder is smaller or a reduced bladder capacity. The only time that this is true is if you're comparing an adult's bladder to a child's bladder. Children, toddlers, and babies have smaller bladders than adults, so they often need to pee more frequently.