I’m often struck by the fact that, if I’m having a bit of a bad day, I can be hugely lifted by a warm smile from a stranger, or a helpful shop assistant, or a friendly word from someone I barely know. They have no idea my day’s going badly, but they still help.

Occasionally in my life, like everyone, I’ve been through a really tough patch, and the kindness of people I barely know has been doubly appreciated because they had no need to go out of their way for me. Meanwhile, those tiny gestures from people I don’t know all added up to making my day just that little bit better. Of course, that’s only on the days when the people around me were being positive.

I imagine you’ve noticed this yourself. You may also have realised that it has an even stronger effect when you’re consciously aware of it. If you register and appreciate those little acts of kindness towards you, their impact is magnified.

So have you ever thought about the effect you’re having on other people? Every time you smile at a stranger, or help someone who’s struggling to open a door, or say a friendly hello to someone you barely know, you’re making their day better. Maybe only a tiny bit better, but it all goes in the pot with the other people who are lifting their day too. Or helps in some small way to counteract that belligerent driver or grumpy neighbour they encountered earlier. This in itself should make you feel good about yourself every time you raise someone else’s day, so you both gain.

I have a friend whose philosophy is that every single interaction you have with someone leaves them feeling at least a little bit better, or a little bit worse. It’s never neutral. When you start monitoring how you feel when you meet other people, you find he’s absolutely right. It’s almost impossible to come away from even the smallest encounter without feeling invigorated or frustrated or embarrassed or cheered or worried or guilty or positive or inadequate or reassured or ignored or amused.

And you’re doing this to other people, as much as they’re doing it to you. What’s more, if you smile at someone, almost invariably they’ll smile back, which gives you that little lift that smoothes your path through the day. In fact, once in a blue moon I smile at someone who just glares back at me. And you know what? I still feel better than I would have done if I’d glared too. I know I’ve done my bit, offered them a soupçon of warmth, and if they choose not to take it, it’s nothing to do with me. Maybe they don’t know how to receive a friendly gesture, and perhaps the hundreds of people who nonetheless offer it might slowly help them to learn.