Which is why I am always messing about, braking hard, braking late, trying to lift the rear wheel when braking, skidding a little on purpose when it is wet and slippy. It is all good practice and gives you a feel for how a bike behaves. When it is time to perform that emergency stop for real then it is all ingrained second nature and you barely need to 'think'. The choice is simply 'Do I need to stop and how quickly can I stop?', all the rest just happens because you have done it a thousand times before. You will also be sure that your brakes work fully and your handlebars are not loose....
The people that potter around, braking early and carefully well before they need to, always going slowly around corners and never exploring the limits of grip, handling and control will almost always be the ones that have the worst outcomes when faced with an emergency manoeuvre. The same applies to driving a car. If you have no idea when you are approaching the limits of grip, or how your car handles with a wheel locked up in a skid, or two wheels, then you cannot drive safely as you do not know if you are going to do something that the car cannot actually do (this is never more apparent than when it snows and people suddenly find themselves sliding off the road).