There are many complicated reasons

not something Donald Trump can comprehend, let alone articulate and solve. not something should be explained in a single post. But I can provide a summary.

1.  Different people feel angry for many different reasons.

2. An important reason is everybody else in the world is catching up and so americans do not have the advantage as before like in the past.

3. Globalization: low tech jobs are shipped overseas--and this is not a problem can be solved by closing borders.

4. Greater disparity between rich and poor, partially because of Citizen United.

5. Some poeple are angry at the governments for a variety of reasons.  I personally blame obstructive republican congress.