You may get the point. My background as a Japanese in my 30s may affect how I perceive those periods. I have feelings for the 40s because WWII is mentioned often. For the 80s, even though I wasn't born yet, many people talk about it as the best period for Japan, so I have a concrete image of that too. And the 90s and 00s are when I was a kid/teenager so I have an emotional connection with the period. Other than these, I have weak connections and just think of the current or near-past periods.