No harm done, just while it's not a vocal majority, a majority of people will say that not liking a system because it looks 'kiddy' is not a very valid reason. Not liking the games because they're colorful, or cute, seems a bit off, especially when you're almost certainly missing out on something good then. Never be ashamed to admit something's fun.

On the other hand, different types of games interest different people. For instance, I don't have an X-Box because it doesn't have many games I like. I don't think shelling out $170 is worth it to play Halo, (Hey, I never said it wasn't a good game, just that it's overrated.) and that's the only game on the system I really have any interest in. If you don't have fun playing the games Nintendo themselves publish, than the Gamecube doesn't have much going for you. It would be pointless if every game was ported to every system - then there'd be no reason to have more than one, and so only one system would be on the market. (Which would be an Atari or Nintendo in all likelyhood - Atari by virtue of the fact that they came first, if I remember correctly; or Nintendo because nobody would've had a particular reason to get a Playstation when it came out since the games would be released on the Nintendo, and so they could've coasted simply on their popularity at the time.)

I guess the main reason is to not judge a game simply because of its looks, and don't be afraid to admit when something is fun.