When a man is out of love---which is more frequent than he is in it---he tends to be often witty and humorous. He can always perceive the female world with a grain of friendly cynicism. He could make negative comments on almost any aspects of the feminine life: cosmetic surgery, slimming efforts, fashion, motherhood, in-laws and so on, without any fear of hurting somebody's feeling.

However, love is such a good tamer of one's animal instinct. The cynicism is replaced by sincerity, seriousness; the wording becomes polished and slippery; the heart is filled with warmth, caring, passion and poetry that there is hardly any more room for humor or wit. The sharp tongue will stammer,  the cynical eyes will glow with dreamy gentleness, and the hearty laughter will become silly grins. 

One's sense and sensibility,  judgment and rationality are all poured into this cement mixer of love and in a few minutes they are turned into a bucket of mental stucco.

Conclusion: 爱会把敏捷的心智搅成一团浆糊