I want to say 'thank you' so often!

I know when I say 'thank you' to others I feel happy, so I want to say 'thank you' to others so often.
Well, to be honest, I didn't use to say 'thank you' to others so often because in the past I felt embarrassed, stupid, etc somehow when saying 'thank you'. But now, I have to admit I was wrong then. I'd been making myself feel unhappy by myself!
By the way, when I say 'thank you'? I say 'thank you' when someone has done something for me: e.g., telling or giving me something nice, useful, etc.
Besides, I always try saying 'thank you' with a smile. I sometimes forget to do so though. This is because I'm sure smiles make feel happy, & I want to make people feel happy.
It doesn't cost to say 'thank you' & smile at all, so I want to continue doing so as well as I can & as long as I live.