When you want to give equal emphasis to different ideas in a sentence, link them with a coordinating conjunction (and, but, for, nor, or, so, or yet) or a semicolon.

They acquired horses, and their ancient nomadic spirit was suddenly free of the ground.

There is perfect freedom in the mountains, but it belongs to the eagle and the elk, the badger and the bear.

—N. Scott Momaday, The Way to Rainy Mountain

Coordination can help make explicit the relationship between two separate ideas.

Connecting these two sentences with a semicolon strengthens the connection between two closely related ideas.

When you connect ideas in a sentence, make sure that the relationship between the ideas is clear.

What does being a common form of leisure have to do with replacing human contact? Changing and to but better relates the two ideas.