Don't abuse your friends and expect them to consider it criticism.
Half the time men think they are talking business, they are wasting time.
No man would listen to you talk if he didn't know it was his turn next.
I declare my belief that it is not your duty to do anything that is not to your own interest. Whenever it is unquestionably your duty to do a thing, then it will benefit you to perform that duty.
Instead of loving your enemies - treat your friends a little better.
When a man is trying to sell you something, don't imagine he is that polite all the time.