Get a Thesaurus and learn a new word.

For example I think you are an imbecile, a twat, a wanker, illegitimate, lonely, a buffoon, a malodourless runt, a prick, a tosser, unloved, possibly abused, out of your depth, unintelligent, sexually confused, unimaginative and uncreative. I also think you are a poor excuse of a man, without friends, without the respect of your peers, have an astounding lack of business and/or common sense and are currently only in your job because you kiss arse.

You are a failure, lacklustre, doomed, incomprehensible, a loser, a liar and a cheat.