Help with this poem/meaning?

Propitiation is to atone for or make a sacrifice. The subject is an old man,probably poor and relatively humble. He stands waiting to be noticed, rather than take the step of going to the girl as he may have done when younger.He feels that he is bothering her and may be a nuisance, rather than see that she is actually there to help him. As the poem progresses and she treats him kindly and calls him 'Sir' he begins to feel important and valued until closing time when she makes a facial expression that signals to him that it's time to leave and he reverts to being a lonely old man again but,for a short while,at least,he felt important again.