Manners in Making a Speech
If you are invited to be a speaker, choose the subject that you know well. It is good manners to do some research to add interesting matter to your speech, and not deliver it with a vague knowledge, without much authority on the subject chosen. A speaker who does not know enough and does not research enough can be seen through easily, and people who come to listen to him will be disappointed, feeling sorry for the loss of their precious lime.