No actually I have not. Mainly because I don't let peoples opinions bother me. Just because someone thinks its childish doesn't make it so. I knew girls in their late teens early twenties who love Pooh Bear and Mickey Mouse, I didn't understand it but in all honesty it was perfectly okay. I guess they are cute, my sister is turning 20 and she still loves the Pokemon television show.
Fact is Nintendo games are designed for everyone, not just kids not just adults everyone. As such the games need to appeal to everyone and that includes children. Think about it a second you like Marvel or DC character's? Were they not intended initially for children? Now they appeal to everyone, are you childish for watching SpiderMan3 or IronMan?
Its all psychological, you listen to society and allow society to control you. But fact is a large amount of Nintendo's market share is older people. Just look at E3 and all those fully grown men lining up to play the 3DS the line was five hours long apparently, are you saying they are all children?
You've gotta stick up for yourself, when ever you feel guilty just say to yourself and anyone calling you childish. This is what I like if you don't like it f off. I mean seriously what makes something adult nudity and blood and its not okay for someone to watch or play something lacking Nudity/Blood and profanity?
Infact I find most so called adult content to be immature, that being said I own mostly 18A movies but the fact still remains that Nintendo's products appeal to everyone. Think a second about ToyStory3 for example I know a ton of grown men wanting me to go see it with them. Are they all childish? No they aren't fact is it makes for good entertainment.
You just have to snap out of it, its a dillusion a bad dillusion.