I can't think of any of the disagreeable co-workers I have had that I would call "potvaliant". The most disagreeable one I can think of was arrogant enough to deliver a woman on a surgical ward full of septic cases, after tricking a colleague into signing a consult OK'ing it. Both mother and child died of puerperal sepsis. I never knew him to drink at all.

was arrogant enough to deliver a woman on a surgical ward full of septic cases

Arogance or plain old-fashioned idiocy? Had he never heard of Dr Ignatz Semmelweiss? (Maybe he was asleep during that lecture.)

Dear jheem: the first time I ever saw that bastard he was standing out in the hall with a patient to whom he was giving an i.v. injection from a very large syringe. I asked him:"Please may I ask what you were giving that patient?"
"Anti-tetanic serum. Vy do you ask?" "Did you skin test him?" "No. Vy should I?"
Only to know what the chances were that the recipient might suddenly die of an anaphylactic reaction.