I'd like to think First and Foremost drawings on street walls are artworks. Often humorous for their simplicity and ability to create characters out of that simplicity.
Social commentary is ideal. It is an opportunity to have a voice and make people think, without being famous or having a turn on the soapbox in the park.
However, unfortunately, most "street art" is just plain grafitti - scribbles on an otherwise 'clean surface'. (also known as Tags).
I'm very open to public expression, (what's life without it?), but the 'scribbles' are an ego driven exercise. I don't see the aesthetic quality in them.
I love love love street art that makes me smile, whether because it's quirky,
or that some clever, bold person/people have made a social comment worthy of being heard.