Appropriate way to reject an offer

Question

I have three case scenarios here:

這是一點心意，請你收下。

Please accept this (gift/money as an) appreciation.

我請你吃飯吧！

Let me treat you a meal!

加入我們的團隊吧！

Join our team!

As far as I know, in the first case, rejecting the offer is rude by any mean/for any reason. Nonetheless, in the second and third cases, many factors, other than personal will, can play a significant role in the decision of whether to accept the offer. For instance, one may have already planned out his schedule of the day and cannot allot time for socializing. Yet, it seems to be rude to directly reject the offer regardless of the reason. Is there a proper way to reject these offers, especially when the person who gives the offer is more superior in terms of age or social status? What are some possible replies to these offers?

By the way, if I have any improper cultural statement(s), please point it out!

Thanks in advance.

Answer 1

List your good points.

Meaning instead of outright rejecting this person's offer, you say, "I already have such and such already," you get the picture. Emphasize that you are very well off, no need for gifts and such. So if someone offered a gift to you, you could say, "Thank you, but I have a lot of such and such." And the good ol' "I'm on a diet" works well on Chinese too :)