Final answer:
Mark Twain expresses a sense of resentment and frustration about the end of keelboating on the Mississippi River.
Step-by-step explanation:
Based on the excerpt from Mark Twain's book Life on the Mississippi, it is clear that he feels a sense of resentment and frustration towards the end of keelboating on the Mississippi River.
Twain describes himself as a skilled steersman who has to do all the work while Mr. Bixby, his superior, takes on a more leisurely role.
He expresses his confidence in navigating the river and finds the idea of fearing any crossing during the day preposterous.
This suggests that he cherishes the time when he was actively involved in keelboating and feels a loss now that it has ended.