In the book On Being a Photographer Bill Jay and David Hurn discuss the criteria that a photographer might consider when deciding what to shoot as a long term commitment.

Accessibility and interest were two significant factors, after all there's little chance for photography if your subject bores you and happens to be extremely difficult to get to. This sounds entirely reasonable and sensible but recognising that is only the first step in the process. What to shoot... what to shoot...?

Contemplating this one Sunday morning I found myself becoming increasingly annoyed by the dog. His habit of repeatedly picking up a tennis ball and dropping it on to the carpet in an attempt to get some attention is something that I have become sensitive to. Thump, look at human, thump, look at human. Over and over....why do I put up with it?

Perhaps, I thought, there might be some interest there so I thought about it and quickly discounted photographing molested tennis balls. The dog might as well make himself useful.

Murphy is a bad tempered Goldendoodle dog who lives with me and my family in suburban Hertfordshire, England. [This] is his blog.

NB: People photographing their pets may well have a bit of a reputation among photographers for naffness...the belief that the pet owner considers his or her animal to be wonderful in some way and that such wonderfulness just needs to be shared. Rest assured that I do not hold any such sentiments. He is simply a photographic subject, no more wonderful than a blade of grass or a mountain sunrise. Thinking about it, I don't even like him very much.