Trump wants to spend tens of billions of dollars on a wall that will break many American acts and laws (he'd basically have to get SCOTUS, Congress and Senate approval) that won't actually accomplish what he wants it to accomplish. This wall is pretty much the cornerstone of his entire campaign, and appeals to the xenphobes and racists.
People claim he says what's on his mind, and that's somehow a good thing, so they've begun emulating him and harassment of spanish american citizens is at all time highs.
He wants to implement a war crime that has been proven ineffective, and is one of the things that just breeds and justifies more terrorism, torture.
He'd put us at odds with Mexico, our third largest trade partner and our southern border. So these people not only want to fuck over business trading, they want to jeopardize national security.
There are many more but...
He's not a self made man. His daddy gave him so much money, and he ended up losing most of it only to have daddy bail him out. What success he has had is in having lines of clothing and other products made in China, and his buildings (like Trump tower) were made by illegal immigrant labor. He's stuffed the pockets of politicians to try and get his way, and even after sending them money has sometimes had them fail.
He bullies and harasses people to try and get his way. The few times people he has threatened to sue didn't give in, he lost BAD for harassing them. When dealing with investing, he lies about numbers to make his deals more favorable. Much of what he does to make money is borderline if not blatantly illegal, and he has declared personal bankruptcy several times.
So not only is this man a lying, corrupt, racist, hypocritical asshole, but despite all the weight he throws around, he hasn't even been successful in the relative meaning of the sense. If he weren't born to a swindler father with millions of dollars to shove his direction, he would have grown up a very meager existence as a redneck bully who worked in middle management.
There's a pretty solid reason why liberals smart people see Hillary as the lesser of two swindling shills. Her corruption is a candle next to Trump's sun-like radiance of corruption.