What are they?

They are shoes which aren't made using animal products. (And no, you will not need to feed them carrots and peas.) 

Why are they a pleasure?

Well, that depends on whether you like them, but they do come in a lot of styles and shapes. 

A vegetarian boot by Vegetarian Shoes

Where can I find them?

In some shops or online. You can order them from Vegetarian Shoes, for example, which started as Veggie Shoes in 1990, and sells shoes made of a synthetic material which feels supple and lets your feet breathe.