The wedding guest begins his morning with the expectation of a good time. He is thinking only of the fun he will have at the wedding, and his thoughts are really rather shallow. However, he is accosted by the ancient mariner, who insists on telling the wedding guest the strange, dark story of a voyage gone wrong and an encounter with forces far beyond human control.
The wedding guest sits on a stone and listens. He has no other choice, for he is held by the Mariner's "glittering eye." As much as he wants to go to the wedding and forget this frightening man and his disturbing tale, he cannot. He must hear. He must pay attention. He must grow in knowledge and wisdom.
Indeed, by the end of the tale (and the end of the poem), the wedding guest is "a sadder and a wiser man." Through the mariner's words, he has been touched by the realities of life and death. He has encountered a supernatural world filled with both darkness and light. He has seen in his imagination the soaring albatross. He has glimpsed the ship of death on which Death and Life-in-Death throw dice for human lives. He has seen the fickleness of the mariner's fellow sailors, who blame him, then congratulate him, then blame him again for killing the albatross. He has looked superstition in the face and watched as the mariner finally rejects it in favor of faith in God and prayer, which save him and lead him to love.
Yes, the wedding guest has gained wisdom through the mariner's tale, and he is no longer the man he once was. He does not even enter the wedding celebration when the Mariner finally releases him. Having fun is no longer important. Rather, he must reflect on all that he has learned. His high spirits may have been lowered, but his wisdom has vastly increased.