Can't say it is the worst ever but The Pull of Gravity by Brette Battles is right up there. (I read it yesterday). The main character (IMO only)was full of introspective blather and intent on justifying/aggrandizing his role as one living of the avails of prostitution and general degrader of humanity of either sex.
Icky, boring and bad taste in mouth. Introspective blather went on for chapters at a time as did backstory. Blather/backstory/blather with a few glimpses of the main story randomly interjected. Should have been written as a ten page antholgy filler to make the other authors look good.
Very fast reading however as you pretty well knew what was going to happen next, and surprisingly devid of explicit sex considering the POV.