Nine hairdressers confess to completely ruining their client's hair.

Hairdressers have a tough job. A client’s entire hair happiness is in their hands the second you sit in the salon chair.

Of course, most of the time everything goes to plan. But what happens when it all goes wrong? In a recent Reddit thread, hairdressers shared the worst mistake they’ve ever made on someone’s hair, and how they recovered from it.

While we’re keeping our fingers crossed that it NEVER happens to us, hey – at least they’re honest.

1. Colour switch

“I did a doozie as an apprentice. In the colour range we used we had these two colours, 22-0 was black and 0-22 was matte (means green) concentrate. My genius boss had them pretty much next to each other. A lady comes in to have her white as snow roots touched up. Guess which tube I grabbed in my inexperience?” wrote one user.

“Luckily her reaction was to laugh her arse off, then gently tease me every four weeks for the next six years. She was a pretty cool lady. I did immediately fix it, but khaki roots with black ends was interesting for the five minutes they lasted.”

Watch: Mia Freedman’s hairdresser Byron Turnbull reveals the secret to a great haircut. Post continues after video

2. Wedding nightmare.

You don’t have to be a hairdresser to witness the carnage.

“I was getting my hair cut next to a woman in foils talking about her wedding the next week. Her hairdresser tried discreetly to wave my hairdresser over. The bride-to-be is oblivious to the ‘oh shit’ moment they are witnessing as they check the foils. My hairdresser apologised but asked if she could pause my haircut while she helped the other girl out. In my mind I was thinking, ‘I am not missing this, where’s the popcorn’,” wrote one user.

“I felt so bad for this poor woman by the time I left. Essentially she had given her a chemical cut right where she folded the foils, so not only was the woman left with orange/yellow tie dyed hair since they had to immediately remove the bleach, it was at least six inches shorter than when she came in.

“The chemicals used were so strong they damaged the hair to breaking point – that point just happened to be where the hair folded in the foils. Think bending uncooked spaghetti in half… You could have mopped the floor with everyone’s tears.” (Post continues after gallery.)

3. (Not so) Pretty in Pink.

“The rep forgot to inform us of a minor change to a colour, and they made the reflect stronger… the pink reflect. So when we used it to tone a ladies blonde to rosy, which we’d done the same way a million times before, it went bright fu*k off pink,” confessed a Redditor.

“Everyone involved basically sat around laughing their arses off. The client thought it was screamingly funny!”

4. Hot hairstyle.

“I once promised a very curling iron-phobic woman that I would not, nor have I ever, burned someone with a curling iron. I proceeded to curl a section of her hair when she flinched and I burned the fu*k out of her ear.”

Image: Universal Pictures

5. Purple mane.

"My client wanted a purple fringe so I lightened it and mixed up the purple cocktail adding extra purple. When I washed it out it was red," confessed one user.

"I was so embarrassed I apologised and gave her a discount. Not using that cocktail again. Fortunately she forgave me though."

6. Bald patch.

"My worst when I was learning how to cut male hair. The guy told me he wanted a basic cut - clippers on the side, scissors cut on top. 'Okay, I can handle it,' I thought. As I was blending the sides in with the top using my clippers with no guard and a comb, I went too close and zonk... a nice bald patch in the back of his head," wrote one user.

"The whole time this is happening I'm trying to maintain composure because they can see every facial expression I'm making in the mirror. After I left the bald spot, I proceeded to cut my finger with my shears because I was so upset/ nervous about what to do. I was bleeding everywhere and had to stop, get a band aid.

"The whole time I'm debating what I should do. Needless to say I didn't inform him of his nice new bald patch and let him have that haircut on the house. I felt TERRIBLE but I never made that mistake again!" (Post continues after gallery.)

7. Colour chaos.

"My mum is an ex-hairdresser and once accidentally dyed someone's hair pink because a tube of colour was marked wrong... She apologised and fixed it, of course."

8. Toupee trouble.

"My wife is a hairdresser and happened to be talking to a co-worker who had a customer at the time. The man was Indian with a thick accent, so the hairdresser couldn't understand him well. Besides the lack of understanding and being in a conversation with my wife at the time, she didn't realise the man said he was wearing a toupee," wrote one user.

"She had already started cutting the mans wig before realising what she had done. She blended it in the best she could."

9. Bleach dreams.

"While in school I was bleaching a woman's hair using a slow developer (10 per cent, it takes longer to bleach the hair but as a student I wasn't super fast so I liked it). The teacher saw I was running behind and had me use 20 per cent (which develops a bit faster) for the final foils in her hair," wrote one user.

"When it was time to pull the foils out and I forgot that the last four foils had been 20 per cent! I quickly unwrapped them and could feel the heat generated from the chemical reaction. The hair was barely holding itself together and the hair shafts were swollen and mushy. If you over bleach hair it turns to mush and breaks off.

"I gently washed the chemicals out of her hair, dumped a bunch of protein conditioner in it and never said anything. The client and my teacher never noticed, but over the next few weeks I guarantee those patches of hair broke off. I felt terrible but never admitted my mistake! I never over processed hair again though."

Got a hair disaster story to share? Tell us below.