How are my puzzles?

Today, I told my friend about Puzzling SE and sent him the link to some of my puzzles.

His reply came, "Your puzzles are such a $50$ $96$ $5$".

"What do you mean to say?" I asked.

He sent me this:

Mine is for. Kim = Tree. Rot it.

What did he mean about my puzzles? (I hope he had said something nice. Fingers crossed)

Note: You don't need to look at my previous puzzles to solve this one.

Hmm, this doesn't look good for you, but I'm probably a little off...

He may think your puzzles are a

Nightmare

Explanation:

His note reads "Minus four. Chemistry. Rot it"
I subtracted four from each of the numbers $50$ $96$ $5$ to get $46$ $92$ $1$.
I looked those numbers up on the periodic table to get the letters PdUH.
Then I "rot"ed them backwards by four letters using the caesar shift to get "mare."
Then again, he may just think your puzzles are a lady horse?

• Coz of this. And I am gonna kill him. – manshu May 21 '16 at 14:51
• @manshu Ah, my answer makes more sense to me now :) Are those standard terms or local to PuzzlingSE? – paste May 21 '16 at 14:53
• Local PSE terms. However your answer is cool to me. – manshu May 21 '16 at 14:56