He said something similar a few days ago in an interview with the Associated Press. Asked if he believes the job has changed him, Trump said, “Well the one thing I would say – and I say this to people – I never realized how big it was…. Every decision is much harder than you’d normally make.”One of the broader lessons we’ve learned recently is that Donald Trump is still learning what most of us already knew – and the presidency itself fits comfortably into this model. He believed leading the executive branch of the world’s preeminent superpower “would be easier,” while most Americans were probably aware of the fact that it’s one of the most difficult jobs imaginable.Regardless, his concessions help bring some core truths into focus.For example, when Trump made all kinds of audacious promises during his candidacy, he wasn’t necessarily lying. He apparently believed, quite sincerely, that a president could have extraordinary accomplishments through decisiveness and force of will, and the only reason other presidents haven’t done so is because, in Trump’s mind, they were all idiots.He assumed, out of profound ignorance, that he could take office, bring health care benefits to everyone, cut taxes, defeat our enemies, and eliminate the national debt – quickly and with relative ease – because the only thing standing between the nation and historic greatness was a bold leader like him, who could simply bark orders and deliver results.Trump had absolutely no idea what he was talking about. He sought the presidency first, then got elected, and then discovered what the presidency entails. There’s routine discussion about Trump’s ignorance , but it’s not limited to issues, policies, and current events – it extends to the responsibilities of his day job.Remember, just two days after winning the election, Trump had a private meeting with Barack Obama in the White House, where the Democrat started walking the Republican through some of his duties. Trump, according to the Wall Street Journal’s sources, “seemed surprised by the scope” of the presidency.Six months later, that feeling remains at the fore.Of course, as Trump reflects on his first 99 days in the Oval Office, and he wistfully remembers how much he “loved” his “previous life” – he had “so many things going” – I’d remind the president that his job is voluntary. If he misses what he had, and isn’t enjoying the burdens of a job that’s far more difficult than he anticipated, there’s nothing stopping him from walking away.