It's important to achieve the right tone when you write. If you sound angry, impatient, or even over-formal, you risk alienating your reader.
This is especially important if you are writing to your boss. (See How to Write a Letter or Email to Your Boss for m more help.)
Here are some phrases which make you sound impatient when you write:
1. Could you please...
Putting "please" after "could you" makes it sound as if you have already asked the person to do something, and that you are reminding them again. It makes you sound exasperated with the other person. Instead, you could write "Please" at the beginning or the end of the sentence.
"Please could you send me the details of the insurance policy?"
"Could you send me the details of the insurance policy, please?"
Alternatively, omit "please", as using "could you" is already polite enough.
2. Would you be so kind as to...
This phrase makes you sound almost sarcastic, as if you think the other person is likely to refuse your request. In business, a person doesn't need to be "kind" to do something: it's generally their job!
Instead, use a phrase such as "Could you..." or "I'd be grateful if you could...." to make a request.
This word makes you sound angry, or that you think the other person is incompetent and can't do their job properly. It's much better to use a phrase such as "Could you.." to give instructions to someone.
4. Immediately / without further delay
Avoid using these. If something is urgent, use the following expressions:
"As this matter is urgent, I would appreciate a reply as soon as possible."
"I would be grateful for your prompt reply."
"I look forward to hearing from you as soon as possible."
"I look forward to hearing from you at your earliest convenience." (Slightly old-fashioned.)