This is also discussed in Nedarim. Many people use chumros in the way of nedarim, taking upon themselves obligations that may not be necessary, even if they are praiseworthy. The goal of such nedarim is to motivate or protect themselves. As gemora says here, you can say “I am taking neder like reshayim” but not “like tzadikim” because the first ones like doing nedarim.
Note that I am talking here about yehidim. The question whether a community in our times does better with more chumros is a separate issue, and I am meikel here allowing more chumros 🙂