Get to the point - fast . Weak beginnings lose your readers when it matters most. Many writers put in a couple of paragraphs of waffle before they get to the point. Maybe it's fear of being rejected when they do. Don't be clever .
Some writers believe so little in their product's interest, they try to be funny or clever.
If people want to be entertained, they watch TV or go to the theatre. Look at the letter with the cheque pinned to it. If it succeeded, it will have been despite the gallant endeavours of the writer. The opening is devoted to self-regarding prattle. It is about the writer, not the reader.