Actually, questions like this that are highly subjective and are basically polls are not permitted in this subreddit. Your question would be better suited for /r/history or /r/askreddit.

Thank you.

This is perhaps less "said" than "did," but Theodore Roosevelt thought so poorly of the presidency of William Howard Taft, a man he had helped elevate to the position, that he ran against him for the Republican nomination, and, failing to secure it, created a third party (the Progressive or "Bull Moose" Party) for the purpose of defeating Taft in the general election.

When Roosevelt was President, he was quite a fan of Taft, remarking upon his appointment of Taft as Secretary of War, "If only there were three of you; I could appoint one of you to the Court, one to the War Department and one to the Philippines." Roosevelt helped get Taft the Republican nomination in 1908, having declared that he would not run again (he served most of McKinley's term and a four-year term in his own right). However, during Taft's presidency Roosevelt became more and more disillusioned with him as Taft departed from many of the progressive ideals Roosevelt had championed. When a movement began in Taft's own state of Ohio to nominate Roosevelt for the Republican ticket instead of Taft, Roosevelt not only refused to demur but said, "I am really sorry for Taft. I am sure he means well, but he means well feebly, and he does not know how! He is utterly unfit for leadership and this is a time when we need leadership." Despite Roosevelt's success in many primary elections, the nomination ultimately went to Taft. Roosevelt then created the Progressive Party and ran on its ticket.

Although Roosevelt did, indeed, garner more votes than Taft, the overall vote was split and Woodrow Wilson was elected President. So, Roosevelt not only helped engineer the defeat of a sitting President, but relegated him to third place in the election.

(Taft arguably won out in the end; he had never really wanted to be President, preferring the job of Chief Justice of the Supreme Court, to which he was finally appointed by Warren G. Harding in 1921.)