Talking of conversation.... There must, in the first place, be knowledge, there must be materials;--in the second place, there must be a command of words;--in the third place, there must be imagination, to place things in such views as they are not commonly seen in;--and in the fourth place, there must be presence of mind, and a resolution that is not to be overcome by failures...

Samuel Johnson (1783) in Boswell's Life of Samuel Johnson