A welcome mat cannot replace the feeling created when the door opens.

Signals of welcome are cheap and easy to install. What people actually register is the half second when the door opens: whether the face changes, whether the greeting is for them or for the interruption they caused, whether they are being received or processed. The mat says the intention. The doorway says the truth.

The same applies to any greeting you give, in a shop, on a call, at your own front door. Try noticing what your face does in the first moment this week. That moment is doing most of the work your polite words are trying to do.