Department of human resources in every industry. Despite the name, they are not there to help the employees. They are there to keep the employers out of trouble.

Funeral Business. Guilting little old ladies into spending money they don't have to give their husbands a funeral "they deserve".

Recycling. A lot of stuff gets shipped to Asia or just dumped in a landfill.

College book industry

Insurance. Life insurance, car insurance, health insurance, whatever. People tend to trust insurance companies, which is nuts. Nice-seeming people wearing nice business clothes, sometimes in a nice office, with nice, neat forms to fill out and nice, long contracts to sign. Everything seems proper. Everything seems fair. These companies DENY claims at every opportunity. That makes up a lot of their profit, the denial of valid claims. The more you pay per month the happier they are and nicer they seem, but that doesn't make them any more likely to give all your money back (and then some on top) when something supposedly insured-against happens. If an insurance company CAN deny any claim, they WILL. It's pure profit. Then they'll often raise your rates, seemingly as punishment for daring to file a claim.

Fine art dealers. Apparently it's a massive unregulated "grey market" that is largely about money laundering.

Healthcare (at least in the US).

Nursing Homes

Clothing donation bins . It all gets sorted and separated and sold . The trash gets donated at the very very bare minimum required . 12 years ago my old warehouse landlord had a $50 million dollar business just sorting the clothes . Vintage/ designer stuff got sold for top dollar . Medium quality sold in bulk S**t quality sold in bales by weight Garbage quality donated They had 20 employees just sorting belts he told me lol . Same goes for book donations ( better world books , thrift books ) . It all gets sold on Amazon and the trash recycled or exported to 3rd world countries . Less than 5% of PROFITS got donated and since they where non profits executive pays where sky high and corporate profits beat zero

Cosmetics. The industry is highly unregulated and there’s not a lot of consequences for making false or misleading claims about products. Who knows what they put in these things.

The wig industry. There are pretty much only 2 wig makers in the world and they repackage the wigs according to what company you buy from. So a Beyoncé at one company, might be another company's Auburn blonde. Also when I worked for a company we had a lifetime guarantee on the wigs, so people would have it for a few years then return it. All we did was wash it in an industrial washing machine, restyle it then sell it as new.

Anything related to eye glasses.

The addiction treatment industry. Trust me, there are some good program, but a lot of very greedy, evil people that capitalize on providing you treatment, then you relapsing, and getting you into the cycle of treatment/relapse/treatment. Very shady.

Not exactly shady, but the restaurant/bar industry is pretty wild. Everyone is on drugs and sleeping with each other. Highly recommend, it was a great time.

Realtors.

The defense industry. The largest defense contract ever, the F-35 joint strike fighter, is a cost plus contract. Meaning there was no fixed price. Lockheed gets paid whatever they spend plus a percent as profit. Trillions of tax dollars will be spent on it.

Automotive repair and it is getting worse. What we need is investigators that take vehicles in with known problems and prosecute the criminals that misdiagnose or just plain sell parts and services not needed. In the 80's California shut down all of Montgomery Wards service departments in the state for abusing customers.

Hearing aids. Lots of unqualified people selling hearing aids with a 500% markup or more.

Car dealerships including both sales and the service department. When my car was still under warranty I used to take it to the dealer for service. Every single time I'm there for an oil change they do their scare tactics; we recommend this service. Whenever I ask, do I really need it they always say if you skip it this and that bad thing will happen. One time they did a brake job on all 4 wheels. The following appointment they again said I need a brake job on the rear. I was so livid and asked them, what do you mean I need a break job? You just did it on my last appointment! So, what did I pay for the last time I was here? I caught them with their pants down. The service manager apologized (didn't really work, I was still mad) and said they'll do the rear brake job for free. I never did get a proper explanation but it this happened years ago so I don't remember. That was the last time I went to that place for service.

Property management

Fertility industry

Most consultancies. It’s very rare you get a specialized service. They come up with a common method for doing things, apply it to most projects, and charge thousands a day for it.

Universities and Colleges.

Many nonprofits are extremely Shady. I was program manager for one of the larger nonprofits in America. I didn't know at the time, my real job with teach corporate Executives, how to make millions using the non-profit system. Worst job I ever had. I left after 6 months. Don't get me wrong, I am not saying all non-profits are shady and bad, they're not. Most are not. However if you want to make an ungodly amount of money, nonprofit is great for that. Just make sure to give up your morals, your conscience and your values.

At least in Toronto Canada, the Towing industry is really dark and run by organized crime groups. There’s basically a turf war between the few companies that had lead to assault and murder of competitors, and fire bombing of tow trucks.

Almonds. They suck California dry of water.

High end sports memorabilia and high end used cars. Just legalized money laundering that often times is never reported. Game used Brady jerseys sell for $500k.

The Non-Profit Industrial Complex. Turns out, a lot of do-gooder liberal types are shady hucksters just like right wing grifters. They do funny things like acknowledge the original natives of the land they're on while intimidating and pressuring employees not to form a union.

The 'financial services' and 'financial advisors'. They portray themselves as organized and honest but they're stealing a lot of us blind.