Our first president, George Washington, was elected more or less unanimously. He was the only president in our history who didn't belong to a party, so there wasn't another party opposing him. EVERYONE wanted him as president. In fact, everyone assumed he'd be president for the rest of his life. But Washington stepped down after two terms, I think mostly because he wanted his old life back. He was one of the richest men in America at the time, and owned one of the biggest estates at Mt. Vernon.
In his farewell speech, Washington said he didn't think any president should be in office more than two terms, so as not to grow too powerful, not to re-make the nation in his own image. This became a tradition, with no president running for a third term until FDR. Roosevelt was elected in '32 and '36, and then in 1940, with the Depression seemingly easing and WWII on the horizon, he ran for an unprecedented 3rd term, and then in '44, with WWII raging he won a 4th term.
After that both parties decided we ought to have a law limiting presidents to two terms, and that was the 22nd amendment.
And it's a good thing too. Otherwise we'd probably still have the embalmed corpse of Ronald Reagan in the White House. Reagan's presidential style was so hands-off that he could be president even with advanced Alzheimers. GW Bush was only trying to emulate him!