I lent a close friend of mine a bill a few years back (found out he used it for casino), since then he ignored my calls & texts until I caught him a Tesco's one time doing his weekly shopping, guy looked bummy and offered me £50 on the spot. In the end I decided to write off the debt as the money was just a dip in the ocean for me, we no longer chat.
If I ever owed anyone money, best believe you would get the money the next day pronto, I've never been in the position to burrow money off anyone unless in the rare instance i.e forgetting/losing my wallet at an event.