Anyone who receives a gift or is given a special favor should acknowledge the gift or favor and express appreciation. Nevertheless , many writer express appreciation in appropriately
The cases of expressing appreciation improperly are
1.thanking when it is not necessary.
2.thanking too strongly
In either case ,the thank can sound very insincere and pretentious. To avoid this consideration is required too judge if it is appropriate to thank someone. If you decide it is appropriate to express thank, choose your word carefully. The tone of the letter shloud be courteous and friendly, and added touches of personal attention are certain to impress the addresses
Study the examples that follow. They might give you a clearer understanding