What wonderful replies, God wants us to be happy He is Love. We see in the Scriptures where David danced:
2Sa 6:14 And David danced before the LORD with all his might; and David was girded with a linen ephod.
NOTE:
with all his might, that tells me he was having a lot of fun

The Bible also tells us what the fruit of the Spirit are;
Ga 5:22 But the fruit of the Spirit is love,
joy, peace, longsuffering, gentleness, goodness, faith,
Ga 5:23 Meekness, temperance: against such there is no law.
The Greek word for joy is
chara
khar-ah'
From G5463; cheerfulness, that is, calm delight: - gladness, X greatly, (X be exceeding) joy (-ful, -fully, -fulness, -ous).
How can we be joyful without without enjoying life?
In the book of 3 John we read
3Jo 1:2 Beloved, I wish above all things that thou mayest prosper and be in health, even as thy soul prospereth.
How can our souls prosper without all the fruit of the Spirit? Joy certainly chould be a part of every Christian's life.
How many people would we be able to win for Christ if we were always walking with our faces downcast and looking sad and empty? I don't beleive we would win any.
Christians can have fun in many ways as long as they are Godly.