Caution: Long post ahead
The big mistake people make with the "show, don't tell" advice is to think that it refers to description. It doesn't, not exactly. I actually wish we could slaughter the whole phrase and eliminate it from our writing vocabulary, because it isn't explained properly often enough or in enough places, and it results in huge mistakes for new writers.
"Show, don't tell" is really more about pacing. Level of detail in narrative. It's the difference between a synopsis and a novel. And you don't have to follow the advice universally, either!
It's like this. Say you have a big scene where your protagonist (let's call him Joe) faces down a robber.
Telling:
Joe unholstered his gun and went up to his apartment. The thief was inside. He jumped at Joe with a knife, and Joe shot the man in the stomach.
Showing:
When Joe got to the second landing, he could see over the rail above that his apartment door was open. There were sounds coming from inside. He unholstered his revolver and crept up the stairs.
His heart was pounding so hard when he got to the door that he thought it would bust his eardrums. He leaned back against the wall next to the doorway, took a deep breath, and whipped in front of the door, pistol at ready.
There was nobody in the living room beyond, but the floor was a mess. Papers and books were strewn everywhere, and he stifled a groan when he saw his television lying face down on the hardwood floor. The sounds of rummaging and flying objects were coming from the bedroom to the right. Joe stepped over his scattered possessions gingerly. When he got to the mostly-closed door, he hesitated for just a moment before lifting his leg to kick it open.
The door banged into the wall with a crack, and a startled yelp came from inside. A man in a tan jacket was crouched by his bed, his arms digging underneath it. He pushed himself to his feet, and Joe was startled by the thief's appearance. He looked like a businessman gone without a razor or a bath for half a week. He barely had time to register the man's appearance before the thief leaped toward him, a switchblade glimmering in his hand.
Joe fired, and the man staggered backward, clutching his stomach with surprise.
Okay, not the next great thriller, but you get the idea. The point is not the description. The point is that there
is detail, that there is a slow enough pace to allow suspense and interest, and to ground to the reader in the world of the story. The description aids in this. So does the POV character's thoughts and feelings. There's nothing wrong with saying outright "Joe was startled..." as part of the narrative. You don't want to overburden the reader with cold description, because frankly, it's boring as hell.
There's also nothing wrong with using a little telling to breeze through parts of the story where there's no tension, little of interest to hook the reader. Let's say Joe stopped by the store to grab a pack of cigarettes before heading home to his apartment. Nothing unusual happens at the store, it's not an important part of the plot, you just want to illustrate the fact that he's a smoker. In that case, it's perfectly all right to say:
On the way home, Joe stopped by the drugstore and laid down a ten for a pack of Camel Lights.
That's all you need for the scene. What are you doing here? You're
telling. And it's okay. It's not a crime. You don't have to show every little detail--you just want to show the good stuff. The stuff that advances the plot, or is an important and interesting part of revealing character or setting.
Another issue you're bringing up in your post is the issue of POV. How deep do you go into your character's head? I certainly wouldn't want to make my POV character's "lips curl up into a mischievous smile, dimpling his cheeks". I'd probably favor something like "he affected his most wicked grin". You want to be in your character's head, so external description is a big no-no unless they're looking in a mirror (which is cheesy and over-used for other reasons, by the way).
