He wanted to be an artist. He wanted to paint beautiful scenes, not waste his time on tawdry portraits. But that was a good way to starve: rich folks wanted portraits, nobody especially wanted anything else. So he ended up painting portraits after all, mostly in the southern USA. He tried to stir American interest in fine European art by bringing over some copies... and was then shocked and dismayed when Americans didn't want to see the art he brought over. Apparently, bringing more uninteresting paintings failed to make the previously uninteresting paintings suddenly become exciting. Who could have predicted such a thing?
Morse invented a telegraph system. And he probably believed in the myth of the lone genius inventor. So... he wasn't so good at acknowledging people that he worked with. Or acknowledging that other people had developed telegraph systems at the same time that he did, without peeking at his work. He did invent a superior UI, in the best worse-is-better tradition. His simple system forced operators to learn an alphabet based on dots and dashes. Contemporary inventors, more sophisticated with engineering, had "better" user interfaces that didn't force operators to learn a special alphabet. E.g., you could set up five parallel wires and send a five-bit values; this could light up letters at the other end; nobody had to learn dots-and-dashes. But these complex systems were nightmares to set up and maintain. It was simpler just to have everyone learn the dots-and-dashes. Thank you for that, Morse.
Morse was in favor of slavery. More precisely, he was against abolition in the USA. He thought it was more important to keep the country together than to force the southern USA to free their slaves. He wrote some things about how slavery wasn't really so bad. In hindsight, it's obvious that his views were horrible. At the time, though, there were of course plenty of people who agreed with him.
It was kind of cute at first reading about how Morse crankily thought of himself as a lone genius inventor. But once he had patents and telegraph-company money to enforce those patents, his cranky notions were less cute. He used patents to stop competitors. He thought that any telegraphy system ripped off his ideas.
Kind of a messed-up dude; made for an interesting biography.