12 haircuts and colours your hairdresser wishes you wouldn't ask for.

Image: Instagram @kimkardashian/@kaleycuoco.

Hairdressers are no strangers to weird and wacky requests, but have you ever wondered the styles or cuts they simply refuse to do? Here hairdressers reveal the 12 requests they wish clients would stop asking for – and we’re definitely guilty of one or two.

1. Bright red.

It sits on the cusp of natural and bold, but bright red is one colour ELEVEN Australia co-Creative Director and three-time Hairdresser of the Year, Joey Scandizzo is reluctant to agree to straight away.

“It’s tricky. There are so many beautiful shades of red that really highlight skin tones and features but really bright fake looking red can end up looking really tacky on the wrong person,” he says. (Watch: Mia Freedman on how to get a good haircut everytime. Post continues after video.)

2. Mullet.

Despite attempts, this is one style hairdressers don’t want to make a comeback.

“I did tell a woman no to a mullet, though she kept referring to it as a ‘scene shag’. I explained to her that what she wanted, short on top and long in the back, is indeed the hairstyle we have been trying to boycott for 20 years,” confessed one Reddit user.

3. Silver.

The grey and silver trend took over hairdresser chairs everywhere last year, but it's not without its reservations.

"This is one of the biggest hair trends however you can't get silver tones on hair that isn't nearly white,"  Heather Neiser, stylist at New York's Hair Metal Salon told Mic.

"What annoys me the most is when someone asks for one of these silvery tones and you explain to them that you will have to go through an awkward phase of some warmer tones in your hair you may not want. When they actually see it [they] don't like it and complain. Sometimes there's no instant gratification."

4. Rainbow.

They may look great on Instagram, but don't be filched by a filter.

"When clients show us pictures of these results, we do help them to realise that the shots are digitally produced with photoshop. If the shots are home photos, they are generally not professionally coloured and look awful," says Susana Montero, Managing Director of La Unica Salon.

"We like to remind clients that the colour work is not sustainable in the maintenance, that is, they are quick fading and very hard to reproduce."

5. Blue.

Blue is another colour Scandizzo doesn't rush into.

"You need to have the total look to be able to pull the colours off well and it's a hard colour to compliment just any skin tone," he says. (Post continues after gallery.)

6. Green.

The same goes for other bold colours like green. They may be great fodder for Instagram likes, but the reality requires a lot of effort that many aren't prepared for.

"You need to make sure you have the rockstar style and [be willing to] change your make up to pull these colours off!," he says.

While it can be fun, it's not a decision to be made on a whim.

7. Chunky foils.

Repeat to yourself: Highlight should not look like stripes.

"Something we do cringe at is the chunky foil result," says Montero.

"We do try to guide our clients towards our signature foiling results which are finer and appear more refined."

8. Dark to light immediately.

Kim Kardashian isn't the first or the last person to want to go from dark to bleach blonde instantly. While treatments like olaplex have certainly made the process easier, it's still a request hairdressers won't rush into.

"I've said no to women who wanted chemical services that would have severely compromised/damaged or broken their hair off. The threat was always,'"I'll just go somewhere else then!'" wrote one Reddit user.

"OK. It sucks to lose that commission, but I'd rather not have my name on a disastrous head."

9. Non-committal.

Giving your hairdresser strict instructions of what you want or saying 'Do whatever you want' are both fine, but it's wanting big changes without being willing to, erm, actually change anything is the type of request that annoys Scandizzo.

"There's just one cut I wish people would stop requesting; 'I would love a complete change but I don’t want layers and I don’t want to lose any length'. This really doesn’t give you much room to play with," he says.

10. Pastel.

Pastel hair quickly took over bright colour as the biggest hair trend for the latter half of 2015, but again unrealistic expectations from clients can make this one a hard one for hairdressers.

It takes a patient stylist and customer and plenty of visits, which many aren't prepared for - and that's just after you've reached the bleached canvas required for the colour to really take.

"It takes a lot of time and a lot of money... because it's a lot of work," Neiser told Mic.

11. Two-tone hair.

There's a reason techniques like balayage aren't cheap - skill and precision is required to make hair look good.

"Our biggest 'oh-no!' request is the two-tone effect with the top area light and bottom area dark or the other way around," says Montero.

"I just can’t deal with it, it's wrong on all levels."

12. Ridiculous designs.

Your favourite football team, the Nike tick or your partner's face... just because you can have a design shaved into your head, doesn't mean you should.

"One guy wanted half of his head shaved, diagonally. Like from the corner of his right eye to the back left corner of his hairline. The rest of his hair was a couple inches long and he just wanted to leave it. I tried so hard to convince him to do something else, but he said he'd 'seen it on a guy and it looked awesome', so I finally gave in and did it." recounted one Redditor.

"It looked ridiculous. I remember the way they kind of sighed and said it didn't look like they were expecting. I asked what they were expecting and he said he wasn't sure, but it didn't look like that random guy that he'd seen. He was super nice but I really wish I'd said no."

What haircuts or styles would you like to see banned?