Edit: Source: The 2008/09 financial crisis. You really don't need a specific source here as it's clear to everyone that Banks have done great dishonest disservices to their customers. Wells Fargo's latest news is case and point.
This is a fun statement, because it's vague enough to be defended with "oh, but I meant <foo>".
Yeah, Wells Fargo got caught making accounts people didn't know about. There are cases like Enron. Financial crises, overdraft fees inflated by ordering transactions maliciously, etc.
In the grand scheme of things, though, Wall Street tends to work, and fairly well, and when it has an issue it winds up recovering eventually so you're fine if you're well diversified and don't need to retire next week. The various stocks in the DJIA and the NASDAQ are making real products, have real value, and will mostly still be here in a few years.
You can't say the same for the ICO world.
The only caveat I'd make is that if you have dependents then this sort of fatuous ignorance is nigh on criminal. Otherwise, good luck and I hope you don't completely fuck up your life.