First, read Do users change their settings? » UIE Brain Sparks. Then, think really hard about the way you design your next piece of software, website, object, etc, because 95% of your audience will likely experience it the way they first see it. They won’t tweak fonts, change font size, or anything else. If it’s a TV, they’ll use it on default settings, and won’t switch it to saner brightness/contrast/whatever settings, or retune it to receive more channels. If it’s a computer, they’ll probably never change the desktop picture, screen saver or keyboard shortcuts. If it’s a car, they might not even know that you can change the steering wheel position.
If you change your environment to better suit your needs, you’re not normal. Other people are not like you. Give yourself a pat on the back for exploring, but don’t be surprised when everyone you know is using the defaults, and make sure that you choose good defaults for your projects.