In WordPress core development, user trust is considered paramount. Aaron Jorbin illustrates this with a post quoting several WordPress core contributors, including a response from Helen Hou-Sandí's to a suggestion made in Slack to rewrite WordPress core.
Aaron illustrates that WordPress isn't just software, but software that many people trust not to break or change dramatically in a short period of time. I like this quote from Drew Jaynes:
User trust isn’t something you earn and then just get to keep forever. It’s a maintenance relationship.
Aaron also recently shared committers stats for 2016, including that 750 individuals got props throughout the year — 396 of them for the first time. That's amazing.