What is the deciding factor for you to report someone for harrassment or assault?

I had a negative physical interaction with a large male student yesterday (I am small and female) on campus, and I don’t know if I want to make a big deal out of it or not. It wasn’t anything sexual or injurious, but it did make me feel…not unsafe, exactly, but suddenly less than totally safe in my school, for the first time ever. Definitely a disquieting experience.

If any of you have experienced something that you decided to report or made you consider making a report, would you share your thoughts with me? Obviously every situation is different, but I need a starting point here.