Scary? Yeah, maybe, but ignorance is not a sin in and of itself. Being ignorant of something and then still thinking you are qualified to do it? That's where it gets scary.
And how about the concept of "current limit"!?
A breaker does not "current limit", it trips on excess current, meaning it STOPS the flow of current.
In the spirit of generosity though, if what you are asking is "What is the trip point of a 20A circuit breaker?", it is 20A, at least. In reality there are tolerances and allowances involved, it is not an absolute value that can be predicted with any reasonable accuracy. The PURPOSE of a circuit breaker is to protect CONDUCTORS, and the sizing rules for conductors are tailored to what the acceptable tolerances of circuit breakers entail. So to the previous point, a 20A circuit breaker is what is used to protect 12ga wire. To use 12ga wire, the load cannot continuously (defined as 3 hours or more) exceed 80% of that 20A circuit size, meaning 16A in reality. So properly applied, a 20A circuit breaker should never see more than 16A continuously, and therefore should NEVER trip. It trips when there is a PROBLEM in the circuit that causes the current to exceed the design values. If the excessive current is only 20A, it MIGHT never trip, but not likely. If the excessive current is 30A, it SHOULD trip in a matter of seconds. There is a chart for every circuit breaker that you can get from the manufacturer that shows what is called a "Time Current Curve" (TCC) that you can use to plot out an expected trip time at a specific current level if you really need to know it.