Holier Than Thou - Biblical Contradictions

Should a fool be answered according to his folly?

Proverbs 26:4, "Do not answer a fool according to his folly, or you will be like him yourself."

Proverbs 26:5, "Answer a fool according to his folly, or he will be wise in his own eyes."

"Sorrow is better than laughter: for by the sadness of the countenance the heart is made better. The heart of the wise is in the house of mourning; but the heart of fools is in the house of mirth." (Ecclesiastes 7:3-4, KJV)

"Then I commended mirth, because a man hath no better thing under the sun, than to eat, and to drink, and to be merry: for that shall abide with him of his labour the days of his life, which God giveth him under the sun." (Ecclesiastes 8:15, KJV)