it wasn't much of a choice
You have to realize that lots of people don't approve of the way Trump behaves, but it is better to have a course, impolite person than Hillary Clinton.
Why is Hillary Clinton so bad? Well, I don't thing anyone has ever tried to put it all together. It is really hard to get information because the press here is so intent of portraying Hillary Clinton in a fantastic light. When you read past the headlines, things get a little grittier, however. This is the impression I get of Hillary Clinton from reading the news (not just the headlines). This is not a comprehensive list, just a summary of themes I have noticed. I'm sure some of it is not correct, since there is so much disinformation floating about. This is just the general impression you get from the continual scandals. After reading it, you can see why people would be willing to have President Trump.
Incompetence
Her record on Libya, Syria, Egypt, etc makes George Bush look like a foreign policy genius.
Unfortunately, those seem to be her greatest accomplishments. Everything else she owes to Bill. She got her first law job at the University because Bill got hired there. She got a job at the Rose Law firm when Bill became attorney general. She made partner when he was elected Governor...
This is s woman who had to use her Blackberry for e-mail because she doesn't know how to use a computer. A woman who had her maid print out classified documents because she doesn't know how to do it herself. A woman who sent unencrypted login and password information through the WiFi at Russian and Chinese government facilities and then didn't change her password for 4 years, allowing those governments to freely access her e-mail and probably the DNC and other hacked targets.
Political Dirty Tricks
The multitude of things her former campaign head did for her as head of the DNC seems unbelievable. Providing DNC offices and resources to her campaign but not to Sanders, collaborating with the media to support Clinton, not Sanders, modifying the voter records in Nevada, locking Sander's delegates out, getting the debate questions in advance, etc.
Disregard for the Rule of Law and Sense of Entitlement.
Setting up a private e-mail server to avoid complying with the Freedom of Information Act is bad enough. In doing so, she paid a State Department IT employee (who certainly knew about the FOIA requirements) from a charity to do the work because it could not be authorized by the government. She paid her staff from her charity. She paid for her daughter's wedding from her charity. She had her aide paid simultaneously by the State Department, her charity handling State Department clients, and a lobbing group that lobbies the State Department and claimed there was not even an appearance of a conflict of interest.
When the head of the FBI stated (essentially) "There is a long history of not holding the rich and powerful accountable for their crimes and I will not challenge that precedent", I believe he expected outrage and people to demand justice. I believe he was appalled when Democrats cheered, instead. The amount of perjury committed in the e-mail scandal just seems to be mind-boggling and it is difficult to tell what was the truth and what was perjury.
Corruption and selling out the country
Hillary Clinton's corruption appears to have no bounds. You see report after report of someone who needed the Secretary of State's approval for something and they (1) Donate to the Clinton charity and (2) Book Bill Clinton for a speech. This included selling the US's uranium deposits to a Russian Government controlled company after a $2.5 million deposit in the Clinton Foundation and $1 million to Bill Clinton (deposited in their joint account?).
The whole Clinton Foundation seemed to exist just to direct government aid money to Foundation donors. The aid sent to India, but diverted to a Clinton Foundation donor, is a good example. They took the money, bought expired HIV medications, water them down for good measure, and charged full price for them. The $9 billion in missing Hatian relief aid is another good example of this corruption. Where is it? No one knows. Bill isn't talking and says he doesn't have to.
When she left the State Department, the Obama administration audit found $6 billion missing. Yes, $6 billion. The State Department under Clinton was so poorly run that they have no idea where the money went. Should this go under incompetence, or corruption?
Poor Health
Passing out, then lying about it, then lying about that....
Suddenly developing slurred speech, then almost passing out....
Having journalists fired for even acknowledging that her health is an issue...
Supporters who suggest that she just has 'a leaky heart valve', nothing serious...