Being kind to a stranger costs almost nothing in most cases, a moment of attention, a small gesture, a few seconds of inconvenience, yet it carries a disproportionate weight for the person receiving it, particularly if they were having an unusually difficult day that the kind stranger had no way of knowing about.
For the person offering it, the cost is often lower than anticipated: the awkwardness imagined beforehand, of offering help that might be unwanted or unnecessary, rarely materialises in practice, and most people report the interaction as pleasant rather than uncomfortable once it has actually happened.
What it gives, on both sides, is a brief, low-stakes reminder that strangers are generally not a threat but simply other people navigating their own day, which is a small but genuinely useful correction to the wariness that daily life in an unfamiliar crowd can otherwise quietly encourage over time. It is a small, low-stakes reminder worth holding onto, particularly on the kind of day when the world can otherwise start to feel unusually guarded and cold.