We are all familiar with popular chumros bein Adam l’Hashem. Is there an accepted list for bein Adam l’Havero?
If not, we should learn such from Gemora. Gemora has examples of how special Rabbis behave. There are also halachik discussions where something may or may not be allowed because it may lead to something else. Conclusion is often more permissive. We can learn chumros form the other opinion there.