My "get out in front of this" trifecta:
A. "Contradicting myself" on what I thought of my classmates; and/or what I thought they thought of me; doesn't (usually) mean I was lying about this. It just means whether my most pleasant memories or least pleasant ones come flooding back depends on what mood I'm in. I've lied a few times about this sort of thing but mostly to webforums I perceived as full of people dishonest to each other. And now regret even THAT.
B. "Respondents lie" isn't just something I say when I don't like the poll results. I liked the "people believe in astrology" poll (even though I don't believe in astrology; long story) but I doubt respondents on principle.
C. "Exaggerating how worried I was about overpopulation" and "overestimating how bad it was" aren't mutually exclusive. Reality is, I did overestimate how bad it was (and underestimate how bad the alternatives were) but I also exaggerated even that when comparatively mild expressions of concern got ignored.