Catapults

What if the catapult doesn't hit the same spot after 3 attempts?:) Or maybe the city had weak fortifications, or maybe it didn't have any at all;)
Or maybe it was just luck.
For example, how many times have I taken cities, and the catapult never breaks through anything. Either I took the city faster with other methods than with a catapult.:) I prefer ranged attacks more. Although, secretly, I would like to have a catapult that destroys all walls in an instant:)