I've only been twice in my life. Once when I was 14 (They were just having the breaking ground ceremony for (back then) Disney MGM Studio), and the second time was this past October.
Prior to our recent trip I had started watching some people's Trip Vlogs and I saw quite a few of them got teary eyed on the last day of their trip. I figured "no way we will be that way". But sure enough, on the last morning my daughter and I were kind of sad about leaving. Thankfully none of us had any tears mainly because the 3 of us caught bad colds near the end of our trip.
But since we got home, we've definitely had thoughts of "I wish we were still there". Looking at photos sort of makes it better, but at times also makes it worse
But I look at it the way the greeter at Port Orleans Riverside did. When we were waiting for the DME, he said to everyone there "Come on folks there's no need to be sad". You can't come back if you never leave! The moment you leave Disney Property you can start looking forward to the next trip!"