I suppose I mentally have some version of tiers in that some countries are more interesting and exciting to me than others. Been to Mexico? While I'd still love to hear about your trip, especially if it's to a region I haven't yet traveled, it's not going to get my heart racing quite like someone who says they went to Mongolia. (I'm also just bitter because I had a Mongolia trip planned and booked and had to cancel three days out due to some work stuff with DH.)
Also, having been to Germany is different than having traveled around Germany, but that's harder to quantify. I've been to 46 countries. Some of those, I barely scratched the surface. (In Romania, for example, I've been to one city for about 8 hours. I don't count something at all unless it meets the "bite, site, or night" rule--eaten a real meal, visited a tourist site, or spent the night. And airports don't count at all.) Others, like Germany where I lived for 3 years, I've been fortunate enough to get to see a lot of, though of course there are still many parts of Germany I didn't explore, in part because I want to 31 other countries during those three year, some of them multiple times. So I can say I've been to both Romania and Germany, but they way I visited was clearly very different.
If having "seen" Germany means you went to Oktoberfest in Munich for 2 days, that's like saying someone has been to the US because they went to Disneyworld. It's not untrue, but it's also not the same has having slowly explored, hit some slightly less touristy places, visited different regions, etc.
DH and I have set a "50 by 50" goal--50 countries together by the time we are 50 years old. We are at 44, with two more booked for December. But in general, most of the easy and obvious places are checked so it does get a bit more challenging. We've never been to South America together though, and strangely we've never been to Canada together (each of us has been separately, but that doesn't count). Once we move back to the States next year, Canada will become an easy weekend trip. So I'm optimistic we will make 50b50, but we may be cutting it close. (We are both 43.) We've also talked about whether we want to make sure that number 50 is somehow extra special, though I'm not sure what new places there are that would feel perfect as we've already visited most of the priorities on the list.