This is a third puzzle from the Monoalphabetic Equation series, you can check out the previous one here: #1, #2.
Last night, I went over to my friend's house for our monthly game night. After we spent hours on charade, pictionary and etc., we decided to end the night with an easy simple game but with a fun little twist...
*The following words and letters $(C, Q, E)$ have been encrypted using the same set of Monoalphabetic substitution.
$(1)$ $$\begin{matrix} & C & Q & E & \\ C & lym,lym & bcylg!,qpkc & qpkc,bcylg! & \\ Q & qpkc,bcylg! & lym,lym & bcylg!,qpkc & \\ E & bcylg!,qpkc & qpkc,bcylg! & lym,lym \end{matrix}$$
$(2)$ \begin{array}{|c|c|c|} \hline \mathrm{qplyicb = E}&\mathrm{ycpl = C}&\mathrm{iqcpl = Q}\\ \hline \mathrm{isj = Q}&\mathrm{smiej = C}&\mathrm{skjmiee = E}\\ \hline \mathrm{glpr = C}&\mathrm{rpbgyl = E}&\mathrm{rplb = Q}\\ \hline \end{array}
$$\scriptsize*(use\ E)$$
After the game ended, I made a gravely stupid decision that eventually got me into a serious trouble.
$(1)$ What is the game and what is the addition to the rule?
$(2)$ What was my gravely stupid decision and what was the trouble I was in?
Hint:
Notice the pattern of the words on the same row and then $use\ E$ (literally and figuratively)