loved Vigo, A Coruña, Salamanca, Madrid, San Sebastian, and Bilbao in Spain (didn't make it Barcelona). Loved Florence, Gaggio Montano, Perugia, Venice, Montepulciano in Italy (didn't make to Rome, Naples, or anything much south of Tuscany). Not much of a foodie and at the time I was taking advantage of the Eurail Pass and crashing with friends who were studying abroad.
I want to go back to both those countries with my wife, but we are also always trying to decide whether we should revisit places one or the other of us had been before we met or try to see new places together before we are decrepit like Omeletpants. And obviously, there were huge swathes of those countries I didn't get to see (or she didn't get to see for ones she visited) when we traveled places when we were younger solo.
Pro-tip for anyone who wants to visit both Korea and/or Japan: Fly into Busan and stay around Haeundae Beach. Not only is it gorgeous and less congested than Seoul (which isn't as congested these days as you might think, even with 22 million people), but you can catch a bullet train to Seoul and points beyond that only takes 2 hours AND, you can take a 90-minute hovercraft (with a bar) to Fukuoka, Japan, which puts you 2 hours away from Tokyo via another bullet train.
ETA: Don't let 'Train to Busan' dissuade you.