So citing the opinion of a Daily Kos diarist didn't impress you? Not a problem! I can do better! But we'll get to that in a moment.
First, a lot of my gripes regarding Obama are contained in commenter Cheryl Quinn's post in response to a February 27, 2012 article on Truthdig. She begins with "What's a progressive Democrat to do this election?" and concludes with "Perhaps it is a good thing we have more time to consider our choices for President..." I won't quote the entire response, for I think you are adult enough (despite some of your snide remarks) to click on the link which will take you directly to this comment, and read the rest of this litany of grievances yourselves.
Yet another commenter on this same Truthdig article, StephenS777, recites why we of my position are angry at Obama and won't play the "But the Republicans will be worse!" game. Again, I won't repeat all of his comments, just the specific part -with the original punctuation and grammatical erors intact, which I deem pertinent to my article:
"His defeat, if it comes, will be earned by his record and his actions not because the people he spent years kicking in the mouth didn’t support him. If he does win, so what, it will only be more of the same—best predictor of future behavior is past behavior."
It's now time for me to reveal the better opinion quotation I promised you regarding why Democratic overconfidence isn't a good thing. It comes from someone who I see as being very much in Obama's camp, someone who generally offers excuses when Obama seems to need them, and ignores his flaws when those would hurt. His clear partisan bias gets in the way of his job as a reporter all too often in my opinion. But on this topic, he perceives the lush verdure that you backers can't identify for all the unharvested platform lumber blocking your view. He's E.J. Dionne, Jr. of The Washington Post, the author of the Truthdig article from which I quoted comments above.
Dionne points out that Obama's polling lead "is far from overwhelming." He notes that Obama has not been attacked yet by the Citizens United money, which is focused for now on sorting out which GOP clown, as you all believe, will end up going down this fall. That isn't going to remain the case much longer. As Dionne puts it, the Republicans may already be correcting their campaign problems, evidenced by, "The fact that House Republicans reached agreement with the president to continue the payroll tax holiday..." Why? "...a far more assertive Obama is dangerous to them in a way that the conciliatory Obama of last year’s debt-ceiling battle was not."