He certainly seems to be overcompensating for something, and is almost certainly not fully self-aware that he is both embarrassing himself (due to his advanced age while childishly using exclamations/mock-enthusiam), and pissing off others around him.

He's that guy at work with the novelty tie (probably Disney themed) and 'wacky' socks. When he approaches you quickly find something to do so he can't interrupt your work with yet another 'crazy story' from 35 years ago when he did his Duke of Edinburgh Award and got stranded on Snowden with only a can of beans and some comics... or that time he drank a whole bottle of wine and woke up at the wrong stop on the train... or he might start doing one of his silly voices and impersonating D-List celebrities from the '70s that nobody has even heard of these days. If you're really lucky he will (in a fit of aforementioned overcompensation) start doing his party turn, where through grimacing teeth he has a mini-breakdown and almost crying tells you all that you're 'joyless spoilsports' because nobody wanted to join him in 'wacky banter' or 'jokey' political-incorrectness.

Unfortunately, he's been around so long nobody really wants to get rid of him lest he realises nobody actually ever enjoyed his company, they just tolerated it, and then in a fit of depressive-realism he hangs himself in the canteen. Nobody actually wants him to kill himself, they just want him to shut up and not bother them with his peculiar brand of egotistical lunacy.