In the poem "Those Winter Sundays" by Robert Hayden, the speaker feels guilty when he thinks of his youth because he now realizes that he was indifferent and ungrateful towards his father who sacrificed so much for him. The poet's father rose early on Sundays in the winter; in the dark cold mornings he would light a fire to warm up the house for the family. The father would also shine the boy's shoes. The father sacrificed for his family through hard work during the work week. On the weekend, the father still directed his energies to serving his family.
Now, the poet looks back on those days with regret. He notes that no one ever thanked the father for all he did. He now realizes that love is doing what is necessary to serve others, even though thanks and recognition is often not forthcoming.
The speaker feels guilty because he knows that his father made sacrifices in order for him to have this kind of life. His father got up early to provide for his family. When the speaker looks back, he recognizes this sacrifice.