For me, the more I knit, the more I find I want to alter patterns. I find that learning all the basics leads to changing things. I've also found that while I see lots of patterns I want to knit, I have an idea starting to spring from my head as Athena sprung from Zeus's. Hopefully there will be no need for Hephaestus and his hammer to help this idea out, just some yarn and needles.
I've wondered about designing knitwear. As I'm not a designer, I wonder where the ideas come from. With some designers, it seems they have a favorite stitch that gets incorporated into everything. Think of how you may look at a design and know instantly it's Debbie Bliss or Louisa Harding. I look in Rowan books and can pick out Louisa Harding patterns almost every time without fail.
Anyway, I don't want to be a bigtime knitwear designer. I can't begin to imagine the pressure they are under to come up with new stuff all the time (which leads to reinterpretations of things they've already done over and over again.) However, I wouldn't mind starting to do my own socks. I was reading Wendyknits last night, and she mentioned that she has 76 pattern ideas for socks in a file. She stopped making other people's socks very soon after sock knitting. I find that inspiring. How wonderful to learn the basics and then run with it. That said, I do hope she publishes her trilobite sock pattern. I have a love of trilobites left over from my dinosaur obsessed early childhood.
Be a fearless knitter. Remember, it's only yarn, and you can buy something less expensive to experiment on. Chose a smooth one that rips out easily and give something new a go.