How kids see time is very different than how you see time. Understanding this will be so helpful when you are dealing with giving instructions. 
Children see time as happening slowly, while adults see time as happening quickly. This is due to children getting more visual stimuli versus the stimulus that adults are receiving. When you get more visual stimuli, time appears to pass more slowly.
Your child is absorbing so much information every moment of the day, which is why your child moves "slowly" when getting ready, doing their chores, or doing their homework.
This concept is especially true when you say something to your child like, "We need to leave in 15 minutes," or "You have 5 minutes to complete this chore." Those measurements of time will mean something completely different to your child than it will to you. Because of this, your child doesn't understand why they are in trouble, or you're getting frustrated when the time is up because, in their mind, they still have time.
When interacting with your child, remember there will be a disconnect between how you see time and how your child sees time. Using the ABC's of Behavior, you can help give your child's perception of time a structure that allows you both to get on the same page, reducing frustration.