The rule of:
1. DON'T HAVE A PARTICULAR PLOT IN MIND, JUST WRITE AND LET THE STORY PLOT ITSELF OUT.
The rule of DON'T MAP OUT YOUR STORY AND KNOW WHAT WILL HAPPEN IN THE END JUST AT THE BEGINNING.
And the rule of DON'T TELL BUT SHOW THAT A PARTICULAR THING HAPPENED BECAUSE IT IS MORE INTERESTING WHEN YOU SHOW AND NOT TELL.
The reason why you should break them
Rule 1. If you don't have a particular plot in mind, your story will be disjointed, your story will be full of unnecessary surprises because every scene was improvised and not carefully planned. secondly, you might loose track. thirdly, you will encounter difficulty in rearranging your story, by the time you discover that you have lost track, you must have written far. fourtly, you are bound to get confused because your thougts are not channelled in one direction. you are always filled with suggestions of "what if?" and in the end, this might not interest the reader because a confused writer will only beget a more confused reader.
Rule 2. This rule is similar to rule 1. now If you don't have the end of your story in your mind, you are likely to stray and you might even force some characters to do what they naturally wouldn't do because you want the story to end by force.
rule 3. Showing is a perfect way of telling a story interestingly. If you tell, your readers will just have to take your words for it though he will not have a precise grasp of what you are trying to say but if you show it, it would have a whole lot of effects on the reader; the effect of seeing by himself, imagining by himself and even reasoning by himself. example below.
You want to describe a scene of someone trying to steal at night and you go:
"Except for the region where his powerful torchlight shone, the room was totally dark. His ears cocked for any slight noise. he looked around the empty room, his eyes shone with determination. he opened the cabinet gently and made out with the box of gold. Satisfied, he walked back on tip-toe, locking the door behind him gently."
Now, showing is perfectly appropriate for this scene.
But the case is not the same with trying to show that someone was laughing.
"Timothy laughed" should be the appropriate sentence, just tell. simple! than Trying To Show.
"Timothy opened his mouth wide and let out the air, his eyes watered as he did this."
Now, the reader is left in a bit of vacuum because he is confused about what exactly Timothy did when he opened his mouth. he could belch, yawn, sneeze or laugh. but the reader doesn't know which one Timothy did.
The buttomline is that some actions are perfect by just telling and not showing because they could create confusion when showed. Thank you!

Thanks for sharing, God bless you.

Amen, thank you.

This is indeed useful. Thanks for sharing the knowledge[color=#770077]