One of the best things you can do for others is, do something nice for them when they least expect it. It's not their birthday, anniversary, or Christmas. It doesn't have to be expensive even. But when you do something they know that you were thinking of them. Like a surprise bouquet of flowers.
I agree with your words. I enjoyed one year when chose a little somethign to do each day, whether it be a call to someone or a kind act. I had 2 messages out of the blue today; one offering me a lift to an appointment and the other to wish me well. It struck me how kind and that people recalled a minor detail of a day of mine and were thinking about me when out of sight for them to contact; it made me feel cherished. :-)
I agree random expressions of kindness touch deeply.