Popularity of the sport may depend on the region though.
While I can enjoy hockey, basketball and even a little bit of football, baseball is just unwatchable. I guess you have to be born in it.
That having been said, it's hard to sit still for it.
You see other kids playing it, and that's where the fun is - with just about any game.
Growing up, we liked to play fast-paced games like soccer and tag, and games that emphasized skill like baseball, or even bocce.
I cannot remember a game that any of us thought was too boring to play.
Another somewhat related analogy would be that I was never trained in playing any musical instruments; I never am interested in learning how to play one myself. But when I see an orchestra playing a random classical music (i.e. the kind of music I personally find boring), I still appreciate that they are showing off skill that they practiced to acquire for many years.
In both, scoring events are usually rare, which leads casual spectators to think that not much is happening most of the time. Because of the rarity of scoring events, though, it almost always feels like either team can still win. That's actually a huge appeal, and something often underestimated.
The similarities basically end there, but those two pieces are big parts of the appeal of each sport. It's not the case that someone who likes one will also like the other, but it helps people understand a little better.