Mix a little foolishness with your prudence: it's good to be silly at the right moment. (Odes, bk. 4, no. 12, l. 27)

Mix a little foolishness with your serious plans; it's lovely to be silly at the right moment

As crazy as hauling timber into the woods.

He is a dangerous fellow, keep clear of him. (That is: he has hay on his horns, showing he is dangerous.) [Lat., Faenum habet in cornu, longe fuge.]

Clapping with the right hand only will not produce a noise

When you meet someone you want to know, be very careful on how you sit on the driving seat to examine that person because you may end up putting yourself on a serious examination. Sometimes people lose interest & walk away after a chat because of the type of questions & silly discussions you engage in. Sometimes your highest intelligence end up exposing your foolishness.