[lè bù kě jí]   

乐    不    可    极    享乐不可过分。

享乐不可过分,否则乐极生悲。也比喻做事要有限度

One should not pursue pleasure to its extreme

乐退安贫    乐不可支    乐此不疲    乐昌之镜    乐昌分镜