What are some funny examples of the opposite of good advice?

It’s just a slot machine, what harm can it do?
Vote republican, they are always truthful and have your best interest at stake.
Don’t worry about what you say, free speech, remember?!
You can trust Fox News, fair and balanced.

My friend’s advice on going into credit card debt to buy something unnecessary: “You can always pay back money, but you can never pay back time.” He obviously didn’t understand the relationship between time and compounding interest.

Ask not what you can do for your country. Ask what your country can do for you.

If a thing’s worth doing it’s worth doing badly.

Among the victors are the spoiled.

There but for the disgrace of Satan go I.

If they want it bad, we’ll give it to them bad.