Sorry for saying this, but, I like when the genius doesn't know everything. I mean I'm enjoy when Stan or Mabel know something that Dipper or Ford doesn't. It haven't happened to you, when somebody who isn't a genius/nerd knows something that the genius/nerd doesn't and works?
It is nice when other characters are given the chance to help the smarter characters by providing new knowledge to them. It’s good to set limitations to characters that are smart because no one knows everything and it helps make them seem more human. I feel like Gravity Falls does a good job with this.