This artist's signature is unclear. Does anyone know who it is. And also, why do artists do this to work that has so much effort put in to it?

I guess they put so much effort into their painting because they just enjoy the medium so much. Good artists are also dedicated to a particular style using oil, watercolour, acrylic, and sometimes a mixture of them. Some are good some are not so good. Jackson Pollock painted undecipherable messes, yet now his work sells for millions.

Sorry, cannot identify signature. You should have included the entire painting which sometimes help identify the artist. Also, mentioning how you came by it, where you found it, etc. what country you live in. All of this helps a little.