What is meant by the phrase "in 1900 europeans believed the world was their oyster?

In the 1900’s the European states were feeling pretty decent about their circumstances. They had settlements around the globe, development was good, their music and art were the jealousy of the sphere and they could have their choice of any kind they required. So, when they said "The world's my oyster" it was intended that they could have whatever they sought at the time.

Habit is no concious