From USAF 1966-70.
My observations?
WWII and Korean W Vets were shown deserved appreciation and respect. Vietnam Vets, not so much. In fact as a Vet in college, I rarely brought up the fact that I served. The USAF Veteran's cap that I wear today would have been ridiculed back in the 70s.
I feel especially bad for the Viet Vets who returned with wounds (physically and emotionally). I think that a warmer welcome home at the time would have been more than a little therapeutic.
Whenever we flew CONUS commercially, the first thing we’d do when we deplaned was head to the nearest bathroom and get out of our uniforms, and put on civvies.
When I got out in 1974, I almost immediately enrolled in college on the GI Bill. I grew a beard and grew out my hair, as being former military on a college campus in California in those days was not a popular distinction.