You never know when you are ‘entertaining angels unawares’. When you encounter someone and have the opportunity to do them good, you have no idea if anything good will come from it for you in return. Do it anyway. The world is a small place, really. When you make an effort for someone else it actually increases your good feelings towards them and your pride in yourself. And who knows, one day, in some unpredictable way, it may just come back in your favour.