Glaswegian cussing, crowd work extraordinaire Martha McBrier has been dubbed the Queen of the Free Fringe. Her show at this year's festival launches a campaign against the perennial happiness bully in her hard-hitting and funny show about suicide, country music and not smiling just because the office idiot told you to cheer up.

What is your favourite insult?

I have no favourite insult. I was once heckled with 'I hope you die of your brain tumour'. I don't think he was a fan (I am intuitive that way).

I am generally not a fan of insults, causing as they do, emotional and psychological damage which may drive people to suicide. Therefore, to enjoy insults to a degree whereby I would collect and categorise them in order of preference, would be saying 'I am a sociopath'. I am not a sociopath. I am a do-gooder and bleeding heart.

In fact, I would go so far as to say I hate people who insult people. I would inflict on them the suffering they caused others. Well, not me, obviously, as I am a humanitarian. By the way, your mum works in McDonalds.

You're a firm Free Fringer - what is it you love about it?

I am actually a flexible Free Fringer. I have done eight shows with Free promoters. I love The Free-ness of it; the lack of bankruptcy; the inclusiveness of it; the underdoggy-ness of it. I like the model and have had some great Fringes thanks to the Free Festival.

I am proud that I was the first performer to receive a five-star review in a Free show, in 2006 with Sex Kitten/Corpse, so we have history. Now it is received wisdom that a free show can be just as high quality as a ticketed show.

His Laughing Horsey-ness, Alex Petty of Free Festival, (and many other festivals) is very well-organised and sends lots of helpful emails to performers at various points in the lead-up to the Fringe. These are dead good. I am very grateful to Alex for his continued support and for having me each year.

This year's show tackles the taboo of suicide - not the cheeriest subject for a comedy show. Why did you feel it was important to address this issue and openly talk about it on stage?

It's the last taboo, isn't it? Everything else has been pretty much covered. Suicide is something I feel strongly about and have many years' experience working in suicide prevention.

I believe that it is a human right to take your own life. That might seem contrary to the whole prevention thing, but it really isn't. The minute I think you have no right to do something, I respond to you in a particular way. If I recognise your right to end your life, I will approach you with compassion. I know that many people would argue against that, especially religious people. It seems to me that a main purpose of religion is to remove people's rights.

That said, I believe every life lost to suicide is a tragedy. Men are more likely to take their life than women. That's needing sorting. (FYI I never use the phrase 'commit suicide' as it stems from the days when suicide was a crime). Someone calls the Samaritans every six seconds. Suicidal feelings are very common and should not be silenced. Get it out in the open, then it's less of a threat. Laugh at it, and it's less scary.

And of course, the show is funny. I discuss two particular suicidal incidents that were hilarious. They are funny stories.

We hear that Country & Western music plays quite a big part in your show. What are your three most played Country & Western songs and what is it that keeps you going back to them?

I love Country music. I am a fairly recent convert to it. I sneered at country music when I was young. I remember pissing myself laughing at D.I.V.O.R.C.E. by Tammy Wynette. Now it is my karaoke go-to song. That and Smells Like Teen Spirit.

I now 'get' Country music and I love its simplicity and brutal emotional honesty. Take Ode to Billy Joe by Bobbie Gentry. I have been obsessed with this song since I heard it as a child. It's a song. About a guy. Who jumped off a bridge. It is a most perfect thing. The record company didn't bat an eyelid. They didn't say, whilst wearing cowboy hats, 'Suicide is quite a sensitive subject'. They probably said, 'Hot damn! This has got hit record written all over it' and released it.

Another favourite of mine is Folsom Prison Blues by Johnny Cash and Willie Nelson (I love anything by those two). It's a song. About a guy. Who is in jail. Cash sang 'I shot a man in Reno, just to watch him die'. No one was concerned that the song might come across as a bit 'murdery'. The producers probably 'yee-ha-ed' and asked if Cash had 'any more songs about that there killin'. They loved the human honesty.

I love traditional country music, old-school rather than the modern, poppy stuff.

Sometimes when I feel the blues, and feel in need of a therapeutic sob, I listen to I'm So Lonesome I Could Cry by Hank Williams. I defy anyone not to cry at that song. It is the epitome of a country song: simple, human and beautifully painful. We should all cry more. Crying is the new laughter.

I actually got the show title Happiness Bully from the wonderful show called Nashville. I had never heard the phrase before, then I realised it was a thing. A behaviour that I had noticed and despised, and that someone had named it. Before that, the show was going to be called, 'Isn't it awful when people try to emotionally harangue depressed people into feeling positive when it's completely inappropriate and ill-considered.' I think Happiness Bully is a lot snappier.

How do you want the audience to feel walking out of your show?

I assume you mean walking out when the show has finished. I want them to feel whatever they are feeling, as I have no wish to control the emotions of others. I hope they have laughed in the face of uncomfortable subject matter and would think about talking to someone if they feel bad. That's all.