Curiously, they often know very little... but think they know plenty.
They memorise and recite slabs of stuff that they don't really understand.
Typically, they have a superiority complex.
They don't seem to get that preaching to an unwilling congregation ain't a great strategy for recruiting followers or fans.

Trying to 'teach' people who, as a rule, don't really want to be educated or enlightened (badgered, annoyed, hounded, harassed) by some over-zealous, socially-unaware (incapable of reading the 'I'm-not-remotely-interested-in-talking-to-you' signs) evangelistic boofhead, who doesn't understand that trying to convince, convert, manipulate, intimidate or pressure people into a different way of thinking and being (theirs)... doesn't work.

The things they really desire (to engage, connect, gain approval, earn respect) are the very things they'll never achieve because they constantly impose themselves on an unreceptive and unappreciative audience.
In fact, their strategy (to evangelise the unsuspecting and unwilling at all costs) is the most effective way to alienate and distance people from any particular message or messenger (no matter how good or relevant the message may be).
But still, they persist.
Like the weed, they are resilient and relentless.

"You can't teach someone who doesn't want to be taught."

I learned this lesson a few years ago when I was in Sydney for a conference.
I was doing a workout in the hotel gym when I noticed a lady doing an exercise so badly that I thought she might seriously hurt herself at any moment.
Against my better judgement (of offering advice to strangers), I made a suggestion as to how she might avoid injury.
She told me that she had been training in gyms for twenty years, that being a woman didn't mean she needed help from a man... and to mind my own business.

Great work Mr Percepto.

There are plenty of knowledgeable, well-meaning, 'nice' people with great intentions and honourable motives.... who still annoy the crap out of people because their advice and input is not sought.
For people who are allegedly so enlightened, your average SASHM is typically kinda socially-inappropriate, deluded and unaware.

Alright, stupid.

We know that communication is largely non-verbal (93%) but they don't seem to be able to read that non-verbal stuff.
The 'you're-really-annoying-me-and-can-you-go-away'... stuff.
The 'I'm-not-remotely-interested'... stuff

"Now Kevin, when I put my fingers in my ears and turn my back on you... that's a sign, okay?"

I call them pronoid; the opposite of paranoid (one more for the Harper dictionary).
They actually think people like them, find them interesting, fascinating and amusing and want to hear what they have to say... despite the obvious (to everyone else) lack of interest from their would-be audience.

They don't interpret rejection like you and I do.
You and I would think "Mmm... this Dude's totally not interested in what I've got to say, (therefore) I'll shut up."
Your typical garden variety SASHM would tell himself "it's a good thing I turned up when I did... this Dude totally needs me."

The fact that nobody asked for, needed or wanted his input is of no consequence to him. On the contrary, our delusional and socially inappropriate wanna-be guru will get on his soapbox at every available opportunity.

The SASHM comes in many shapes and sizes and from a range of backgrounds.

Here are few to watch out for:

The Social SASHM - She's the one who feels compelled to educate everyone on matters of appropriate social behaviour. "I can't believe she spoke to that woman after what happened.."

The Smoking SASHM - He's always an incredibly annoying ex-smoker who loves to criticise and berate people for doing exactly what he did for thirty years... will say things like, "Hey ashtray breath, d'ya know what that stuff's doin' to yer insides?"

The Nutritional SASHM - Also known as the food police.
Always an ex-fatty (I'm an ex-fatty... don't get precious on me) and seems to have made it her responsibility to comment on what everyone in the room is eating. "Do you know how much fat and sugar's in that"... or the classic "Do you really need that piece of cake?"

The Exercise SASHM - He's usually an ex-lounge-lizard.
"Ran for two hours this morning.. how's your program going Porky?" Is compelled to impress everyone with his amazing fitness regime and incredible biceps.
Wears his hear-rate monitor twenty fours hours a day.
Embarrassing.

The Fashion SASHM - Her wardrobe is her identity.
She is label-obsessed. "Don't you have a mirror in your house... did you wear those pants on purpose or was it a dare?"
It could be a potato sack but if it's got DKNY on it... she'll buy it.

The Relationship SASHM - Has usually had three hundred and seventy five failed relationships of her own.... but incredibly, knows exactly what you should do with your love-life and constantly comments without invitation.

The Financial SASHM - A.K.A... The 'let-me-help-you-get-rich-in-no-time-by-playing-the-stock-market'.... coach. These are people who seem compelled to help you make money... but actually have none of their own (love talking about their 'portfolio' though).
They work at Big Bill's Burgerhouse.

The 'I've-done-a-two-day-life-coaching-course' SASHM - The scourge of the new(ish) millennium. A.K.A.... The 'my-life's-stuffed-and-I'm-kinda-dysfunctional-so-let-me-help-you'.... coach.
Stay well away.

Well there it is; a quick overview of an interesting group of people.
Tell us about your encounters with, or thoughts on, the Self-Appointed, Self-Help Messiah.
You may even have a category (or two) to add.