Why avoid the word “please” in error messages? [duplicate]

Question

Possible Duplicate:
Should an interface ever say “please”?

According to Windows User Experience Interaction Guidelines (UX Guide) for Windows 7 and Windows Vista:

Avoid the word "please," except in situations in which the user is asked to do something inconvenient (such as waiting) or the software is to blame for the situation.
Correct: Please wait while Windows copies the files to your computer.

I always use "please" in my error message for it to be polite, like

... please enter a value in the username field.

Why do we need to avoid the word "please" for errors like this? Won't adding "please" make the message more polite?

Answer 1

Not only Microsoft uses the guidance on avoiding please in Error Messages. OpenOffice, a Microsoft Office competitor, also lets the developer know to avoid please:

Use “please” only rarely, if ever. Sometimes lengthy instructions or error messages might need a touch of politeness added to one of several sentences, but generally, do not use “please” in English. If you still feel the need, at least avoid using “please” more than once in one text or group of sentences. For example, you could use “please” in the initial instructions on the first page of a wizard, but then not on any of the other pages. Simple imperative sentences are always preferred.

However, there are cultural differences. In German the word "bitte" is almost always used in Error Messages, so be careful to use Google Translate or other automated translating services in a Multi-lingual application.

Answer 2

Overused words lose their meaning. It is called Cliche.

If you use please, and thank you for every user action then the effect flattens and you don't have its full strength when you need it to sound meaningly.

Avoid the word "please," except in situations in which the user is asked to do something inconvenient [...]