Yep. N-parents often try to sabotage you by giving you unrealistic expectations and bad advice.
If they teach you to negotiate for unrealistically high salaries (for example), they know you'll have a much harder time with your search.
Or maybe you have an interview coming up and they'll look for excuses to inconvenience you logistically, or keep you up late the night before.
Or they'll try to get you to depend on them for something (like transportation) and then suddenly yank the rug out at the last minute because of "external circumstances" (gosh, the car stopped working!) when it's too late for you to make alternate plans without getting frazzled and extra-stressed before your interview.
Or they'll just give you really bad/tacky advice that will make a poor impression and make you a less attractive hire.
They do all of this on purpose because they know that if you're gainfully employed, they lose some control over you. If you are living on your own, making your own money, living your own life, etc, they no longer have any leverage to punish you with / to keep you dependent.
They prefer to keep you at home forever as a source of N-supply. This accomplishes several things for them:
They get to feel superior. They feel threatened by people they perceive as "better" than they are, and so it puts them at ease to see a skilled/bright/happy person fail. It's crab mentality / misery-loves-company.
They get to seek sympathy. Now they get to go around to all their friends and complain about how you have failed despite all her hard-working efforts raising you. She will complain about how she has to support you, but since she is "such a good mother," she's willing to "sacrifice herself" for your well-being by putting up with you (martyrdom complex).
They get to exploit you. If you're still living at home, it means the parents still call the shots. They control the finances, the transportation, the communication, etc. This also means they can rely on you for free labor (or else they'll threaten to revoke something, etc). If you do manage to earn a paycheck while living near home, they can try to manipulate the situation to take your money.
They may have a fear of abandonment. Some N-parents know, deep down, that they have treated you like shit. They know full well that the moment you get any bit of autonomy or power, you'll leave them behind in the dust. It's sort of like if an abuser hurts an animal and then opens the front door. You know exactly what that animal is going to do.
Long story short, they are almost never acting in your best interests. Seek advice elsewhere and never give your parents any details about your job search.