I highly recommend you do learn how to write your own shaders. It doesn't take much time at all to be able to do your own tweaks and even simple effects, and then it won't be long after that until you're learning more complex effects.
Many users who don't know how to write shaders avoid trying out of intimidation -- the assumption that shaders are difficult. The thing is, most shaders are short (they need to be fast, right?). They use relatively simple maths (except for some "standard" matrix operations that are the same in almost all shaders). And they are visual.
