Why do employers expect you to learn super fast?

I've worked two different jobs this month and my employers have both been old ladies who expected me to learn everything on the first try And I'm thinking to my self well that's what training is for isn't? One of them even told, "I'm going to teach you only once how to do it" Its ridiculous because its not like I'm doing 1 single thing I'm doing a lot of different tasks. Are all employers like this? or have i just been unlucky and had grumpy old women as my bosses