Go with the flow, everyone has their own styles. Plus, what are the chances of you needing a straight line?
Oh boy its not just straight lines. Everything is harder to draw with my fingers without some sort of pen. XD
I saw the end of your drawing requests post, (I've been watching it since I posted). You can't waste it. You might think they're bad, but all artists will do that and all it takes is support from the people who like your art and want you to be happy. And if this post influenced you to make more, its a pleasure to help. If it didn't help at all, I hope something will, and at least I tried.