Switching weapons

Why is it when you bring up a weapon and switch to another weapon it's like trying to grab something out of your backpack while it's still on switching from the knife and switching to the gun should not be that **bleep** difficult or slow.. you should be able to smoothly and seamlessly switch weapons anytime you want while going through a door or whatever it doesn't matter but you can't it won't let you sometimes you have to push the button multiple times putting plates in is the same way why is putting plates in so slow for one plate.