I don't know how the hell Mickey mouse was ever popular during the 1940s, the time of Tom and Jerry and Looney Tunes. Were they funny? No. Were they entertaining? No. Were they creative? Yes but there were more creative cartoons.
How did this little mouse originally get so popular? Some would boil it to him being the mascot of Disney, but that removes the fact that many are still watching this unfunny rat. Does anybody who ever enjoyed Mickey Mouse's cartoons? I have never enjoyed them except for Fantasia, but that does not count.