Passport stamps are like my favorite thing in the whole world—I think this comes from the movie While You Were Sleeping, in which Sandra Bullock's character gets a passport and her life's dream is to get a stamp in that passport. I saw that as a teenager and I guess it left an impression. (Also, I'm very easily amused.) I swear if I ever lose my passport I will cry and cry.
In the beginning days of me having a passport, I was hard pressed to get a stamp. When I took a ferry from Northern Ireland to Scotland I discovered there was no border to deal with and there would be no stamp. I begged the ferry employees to give me a stamp. Anything. That's where I got my sheep shearing company stamp. In Prague, when I flew in, the man at the counter forgot to stamp me. I begged him until a soldier with a gun shooed me away disappointed. Majorly. Mexico never stamps. (When Hanna and I went in 2010 I practically forced border patrol agents to stamp her passport so she could get her first stamp. They poo-pooed me but I would not take no for an answer.) If there's ever a chance for a souvenir stamp such as at Machu Picchu, or Checkpoint Charlie in Berlin, I take it. One of my life's greatest excitements was when I was in Buenos Aires and had to get extender pages in my passport because I had too many stamps!
But: did you know? They aren't just for souvenirs? I'm about to admit something very embarrassing: I just figured out, like sort of recently, that a stamp is a Visa, granting the bearer a certain amount of days in a country. Usually it's 30 - 90 days, but it depends on that country's relationship with your own. Sometimes, you have to pay for your Visa. For example, in most Southeast Asian countries, I paid $15-$40 at the border for my Visa, which came with a dated entry stamp. Sometimes they want your photo, so I always travel with 5 or 6 printed 2x2" photos of myself*. In addition, you have to be stamped out of one country and into the next. And that's how they know if you overstayed your Visa and are subject to a daily fine. And that's why they look through your pages. (I always thought they were admiring my stamps.)
All these years and I've just been handing over my passport to border agents, praying for a stamp because I'm a NERD, but never knowing why. That there was no border patrol at the ferry in Scotland because you were already coming from the UK. That the guy in Prague didn't stamp me because I had just come from Germany.
Sometimes I'm amazed at how dumb I am.