Unprofessional
He had often heard his brothers refer to him as 'unprofessional' because… well, he wasn't too sure why. He couldn't understand why either.
It was Zeus who got angry every time someone said his name in vain causing the thunder to rumble ominously overhead, and it was Poseidon who dressed like he was permanently on holiday.
He was the one who always dressed in complete black, a suitable colour that was elegant and formal, and professional, not to mention the fact that it actually suited his 'job.'
Sure, he occasionally turned into a terrifying humanoid whose body was partially or, more commonly, completely covered in flames, but that was part of his job description. He had to scare those insubordinate souls who thought far too highly of themselves into submission. They would make too much of a mess in the Underworld otherwise, and he certainly hated the messes those unruly souls created.
He sincerely doubted either one of his brothers would be able to do a better job themselves.
They were the ones with the easy jobs. If they didn't like someone they could simply suffocate or drown them respectively, and they had done it many times – you would never be able to guess how many people died from those kinds of things! He had to be creative with how he killed whoever he hated, because otherwise it would be suspicious, and that was all professional.
The fact that the person dying early may have been someone whom he deeply disliked, was purely co-incidence. They had not been fated to die as they had, they had only been in the wrong place at the right, I mean, wrong time. Those accidents were clearly meant for someone else.
It wasn't his fault.
Really. It wasn't.