1. Not using the correct format. As highlighted above, a friendly letter has a stipulated format. Sticking to the format ensures the proper conveyance of the intended message.

A Friendly Opening for a Business Letter. When most people sit down to write a business letter, their first inclination is to write formally -- sometimes too formally.

Depending on the nature of the letter, it can either be written in the friendly or the business letter format. Friendly/Personal Apology Letter ...