Trump has posted a tweet from his @realDonaldTrump account mentioning "Obama" 1,464 times — the vast majority of them negative.
1. Travel: Trump often vented on Twitter about Obama's taxpayer-funded travel.
2. Golf: Another one of Trump's favorite Obama critiques involved the former president's golf outings. He posted 16 tweets about Obama hitting the golf course.
"We pay for Obama's travel so he can fundraise millions so Democrats can run on lies," Trump tweeted in 2014. "Then we pay for his golf."
He also quoted other users' tweets criticizing Obama's golfing habits.
3. Syria: Trump argued extensively against US intervention in Syria, tweeting in July 2013: "WHAT WILL WE GET FOR OUR LIVES AND $ BILLIONS? ZERO."
After a chemical attack killed hundreds in the suburbs of Damascus in August 2013, Trump continued to ridicule the Obama White House's debate over whether to militarily engage Syria.
4. Transparency: Trump also accused the Obama administration of opacity, tweeting in 2012: "Why does Obama believe he shouldn't comply with record releases that his predecessors did of their own volition? Hiding something?"
In 2012, he called Obama the "least transparent president — ever."
The Trump administration said on Friday that it would stop publishing White House visitor logs and that they would be kept secret for five years after Trump leaves office.
Source: Business Insider
5. Experience: Trump also laid into Obama shortly before the 2012 election, saying he was "a disaster at foreign policy. Never had the experience or knowledge."
6: Diplomacy: Trump said in an April 2016 campaign speech focused on foreign policy that Obama had "picked fights with our oldest friends."
Source: New York Times