I think the specific psycho phenomenon is that if there were 5 good things and 5 bad things about dating in the 50s, we generally remember the good things and talk about the good things. Now with tindr there's also 5 good and 5 bad and we say "wow all these bad things suck, back then it was just [the 5 good things that they remember]".

Remembering the good vs the bad probably aligns with someone being naturally upbeat or sad (glass full vs half-full personality).

Also I'm skeptical of that Democrats and Repubs line. In the good old days they got into fist fights on the congress floor.