I would be a terrible marital counselor myself -- I would save marriages only by virtue of the fact that they agreed their counselor was a critical fathead and have something new in common - but I recall an important part from my training. The use of the words "always" and "never" are giveaways that a person is responding emotively rather than logically. "She always undermines me in front of our friends." "He never supports me with the children's discipline." There is no always and never. (If you ever go to a marriage couselor, you can stay one-up on your spouse by remembering not to use unqualified statements like that).
One occasionally sees comments on conservative blogs that Clinton (or Carter) was a completely terrible president. Worst ever. No redeeming qualities. Please note I said "occasionally." More frequently, amidst the scathing criticisms, one will find grudging praise or acknowledgement. I thought Clinton did well on NAFTA and GATT, and showed some real backbone, and I don't mind saying it. For all the mistakes in Bosnia and Kosovo, Clinton had more success in that impossible situation than most others in the last 7 centuries. Welfare Reform, though it happened under pressure, did happen on his watch. Great. He was on balance rather a cipher, neither advancing nor destroying foreign policy or the economy. With the former USSR, benign neglect was an okay thing. With Islamic terrorists, it was a bad thing.
It is this general balance on the sites I am in agreement with that causes me to shake my head in disbelief visiting lefty sites -- even supposedly moderate or reasonable liberal sites. People will claim with a straight face that George Bush is the worst president ever, that the war in Iraq had zero justification and has been an unmitigated disaster, that civil rights have been set back decades, etc. It defies common sense.
You could pick any president at random in history, list up the negatives and ignore the positives, and declare him to be the worst president ever, if you wanted to simply make statements that looked like an argument, rather than actually examining the evidence. Why would that be a valuable exercise?
The extreme statements, the always and never statements, are the tipoff that the writer is not worth reading another sentence of, unless your goal is to teach instead of to learn.