Gratitude gets praised endlessly these days, but Seneca is after something fiercer—he's saying that recognizing what others have done for you is itself an act of moral courage, not mere politeness. A grateful heart demands that we admit our dependence, that we acknowledge debts we can never fully repay, which runs counter to our instinct to appear self-sufficient. When a parent finally thanks their adult child for patience during illness, or when someone publicly credits a teacher who believed in them years ago, they're performing an honor that costs something: the vulnerability of saying "I needed you." That's what Seneca means by honourable.