The Mariner in The Rime of the Ancient Mariner seems to have been a pretty sociable guy before he took that fateful trip down to the Arctic, but now he travels the country looking for former lost souls like himself. His best friend in the poem is a hermit, if that tells you anything. After the experience he has been through, he can't just return to normal society. The idea of going to a wedding is very distasteful to him, for example. The low point of the story he tells is when he is left the only man standing on the ship and must suffer the cursing stares of all the dead men.
The Wedding Guest becomes a "wiser" man at the end of the poem because he recognizes that the story is a metaphor for his own condition.
The Mariner's disdain for appropriate social celebrations like the wedding feast shows that he has not fully overcome his pride. He remains a "devil" of sorts.