There is a version of kindness that runs itself ragged — always saying yes, always available, quietly depleting. Most people who care about being decent have bumped into that version at some point.
I find myself curious about where the line actually sits. Not the line you read about in a self-help article, but the one you discovered the hard way, in a real situation, with a real person.
Did saying no cost you something — a relationship, a sense of yourself as a good person? Or did it turn out that the firmness and the kindness were pulling in the same direction all along?
Interested in both: times it went well, and times it really didn't. Whether you've found a rough principle that holds, or whether you're still working it out case by case like most of us probably are.