Since my commute is also my "workout", I'm generally not in a state where talking is comfortable for me, and I'd prefer to be alone. This is especially true in the morning - the solitude and shifting light are essential for me to come into the day in a good way.

That said, I do occasionally find myself in conversations with other commuters if we seem to be riding at a similar pace. I don't mind easing up my pace if I'm feeling tired, and sometimes prefer taking it easy and chatting than pushing it. Sometimes.