When I started teaching PostgreSQL education courses in 2001, PostgreSQL was the ugly one in the data center. Many of the people who were learning how to work with it were doing so grudgingly because of some specific requirement. They had inherited a PostgreSQL database, for example. As a result, many of them tried to learn just enough to do what they needed to do. The other population of students were serious technologists, die-hard open source devotees who wanted to use only open source solutions and were learning PostgreSQL because they needed a relational database for their operations.