I don't remember the 80s but I always talk about how great the 90s are and I will never stop. The greatest decade, bar none!
For me it's part psychological and part physical- I try to look after myself as best as I can with eating well and so on and psychologically I don't allow myself to feel old. If I think back to an experience in the 90s for instance, I don't think "wow I can't believe that was x years ago, I feel so old". I'll look back with fondness and think to myself I was so lucky to have had that experience in the best decade ever
Also my 20s were a mess, my self esteem was in the toilet, I constantly got with unsuitable men, wasn't happy. Much happier and confident in myself nowadays
Hope that doesn't sound preachy!