It seems to me rather a well crafted tirade, what with its alliteration, and its rhythmic qualities.

Clumsily punctuated, true - it should have rerad:

Shambles, you are a self obsessed, self interested, self important, supercilious, pompous, priggish, paranoid prat. Deluded, devoid of humour, dreadfully boring and disgustingly repetitive.

Considered stylistically, it contrasts very well with the stuff that some people here seem to feel necessary to spew out when they get crossed. I think Shambles could well actually feel quite pleased to have elicited a denunciation like that.