Yeah, I usually try to communicate that I understand that it is important for them and take them seriously. If possible, I would also attempt to find another solution or something like that. Also, if you are someone I have good experience with I would give you a reason.

Yet also, I help if I can and if it does not cost me all that much. It is not like I would be saying only no to everyone around.

This strategy is largely the answer to specific people I deal with and their strategies. It does alienates them a bit sometimes, but it is not possible to keep everyone happy all that time and I am very unhappy with that negotiation I am trying to avoid.