Neelix

Sure, I'll treat this ship as if its mine and the crew's only purpose is to do my bidding

Neelix easily out-performs Wesley Crusher for the "Most hated character on Star Trek" award. He is so annoying, so obnoxious and so stupid, he makes Jar-Jar Binks look like Sean Connery in comparison.

The USS Voyager found this asshole in a debris field which he claimed was his own shortly after Voyager arrived in the Delta Quadrant. One of his first acts was to lie to them so that they'll go rescue Kes. He turned the ship's dining room into a galley without permission and appointed himself "chief morale officer". And he consistently disobeys direct orders from Voyager's officers, which once resulted in his lungs being stolen by Vidiians but he still didn't learn from his stupidity. He also has a habit of bursting onto the bridge or command staff meetings without authorization and for no purpose.