FACT: I do not always have a negative impression upon first meeting someone. In fact, it's quite rare. I try not to.
However, throughout the course of this year, I have thought several people were kind of odd or weird or unmotivated or unintelligent or.. whatever. And every time I got to know that person better, I grew to love and appreciate them and was ashamed for having thought said thought.
I have also found that it is best to give people the benefit of the doubt. In all things. I now try to assume the best of people. That perhaps so-and-so had something catastrophic this week, which is why they didn't follow through on something. Or that the person that cut me off was in fact rushing a dying loved one to the hospital. You can see these scenarios can get ridiculous, but they help me refrain from judging.
Well these were some findings of mine throughout the past year or so. Findings that are universal but that I never really paid much attention to. I'm sure these things are already practiced by people like you, but I am happy to make the change, no matter how late.