It usually doesn't look like that though.

Some weird or really old lenses can have effects like this though.

Photography word for the out of focus bits. The design of the lens, shape and quantity is aperture blades, maximum aperture size, distance to the subject, all kinds of stuff make the blurry bits different. Phones often try to fake this with a portrait mode setting.

A bundle of flowers

You can make custom bokeh patterns, y'know.