Show Not Tell

"My Room Was a Mess"
Look at the two examples below and notice the differences between the two writing samples. If both have some specific detail and a basic storyline, why is one telling and the other showing?

Telling

I was so mad at my mom! She told me I had to clean my room and I had so much homework. She could be so frustrating sometimes. I walked into my room and I couldn't believe it. There was gross stuff everywhere. Clothes were pouring out of the dresser drawers, posters were falling down, laundry was everywhere. It was digusting. I started clearing off the floor first. Then I got some 409 and sprayed everything down. I piled stuff into the laundry hamper and finally vacuumed. It was so much better. Finally, I had a clear desk to do my homework.

Showing

Cheerily, I walked home from school, entered our yard and strolled in the front door. I grabbed a few cookies and a glass of milk from the kitchen and trudged towards my room, dreading all of the homework I had.

As I grasped the knob of my door, I sniffed curiously and a strong odor emanated from the gap below the door. I decided to ignore the smell and open the door, but it wouldn’t budge. I tried again with no results. Looking around to make sure the dog wasn’t nearby, I set down my backpack, the cookies, and the milk. I firmly grasped the knob with both hands, turned it, and pushed—no results. Once again, I rotated the knob and pushed with all my weight against the door. I could feel the cool wood against my arm and sense that same foul odor waft by my nose. With all my strength, I pushed again and felt the door move an inch. From the crack, I could see the immense pile of clothes blocking the door. A black sweatshirt that I hadn’t seen for months was jammed halfway through the gap under the door. I began to tug at it and heard the sound of material ripping. . .