I believe Obama was an ineffective leader, especially when it came to foreign policy. He wouldn't say 'no', or stand up to, the arab, (or muslim, whatever) excesses that were accelerated during his time in office. It was only because of the American /threat/diplomacy that many possible conflicts in the area were being managed(ish). He also entered a dangerous treaty allowing a certain amount of nuclear freedom to Iran, and refused to commit his country to any kind of intervention in many sensitive topics or areas.. Due to his ineffective foreign policy thousands of people have died, all because the fanatics knew they could get away with their excesses as the American government stood back, (and allowing the Russians to step into the vacuum that was formed)
As a result of his Obamacare many average Americans are (were) paying more than was easily sustainable for their medical care than previously, (this was told to me by more than one American couple), and whilst they didn't mind paying more, what they were called to pay was excessive, and increasing all the time. it was too much, too soon, and is now about to collapse.
His dislike/disrespect towards the UK is reasonably well known(the Churchill bust incident rolled on for a while), and it would seen that his wife was, apart from a very arrogant woman, despite the media's support, quite the racist.
I don't know what life in the States is like, but I do have a few friends, of both political parties, who I stay in touch with, and when I read their comments, along with the media, I get the feeling that he wasn't very effective in the long term, and lets be honest, we haven't heard a lot about his presidency since he left, other than to changes that are in the pipeline, (not all that I agree with).
I never liked the man, and he did nothing to endear himself, as far as I am concerned.
As I stated previously, I didn't particularly want Trump to win, but I did want Clinton to lose, and though I didn't particularly like him, neither did I dislike him, (too much)