I have to step in here to defend "non-trivial".
Perhaps it is abused as a term by the population at large, but I'm reasonably sure it has its roots in theoretical computer science and maths. It has a meaning that is distinct from "complex". It means that something requires something more than pure mechanical verification or straightforward inspection.
A painter could use "non-trivial" in a sensible way. How much effort is involved in X? Well, it's non-trivial, because it involves more than having a look. It isn't estimating the effort, it is instead a binary classification - trivial and non-trivial.
Finally, to answer your question, I don't dislike individual words. I only dislike them once they are combined into sentences.