Is it wrong to have a day to show the preacher appreciation and call it "preacher's appreciation day"?
"But we request of you, brethren, that you appreciate those who diligently labor among you, and have charge over you in the Lord and give you instruction, and that you esteem them very highly in love because of their work. Live in peace with one another" (I Thessalonians 5:12-13).
We should appreciate those who give of themselves to teach us God's word, but designating a specific time to do so is not fulfilling this command. It is the attitude that all Christians should have all the time.
There is no command from God to set aside a day to express appreciation.