Wait until you see Schengen-area visa requirements then: bank account statements, property ownership proofs, education certificates on top of what US would generally ask you for. And then you get exact-dates-of-trip visas (compared to US issuing 3-year or 10-year visas) — or, well, get denied simply because (even if you had a visa that allowed you to travel to that same spot a month ago).

Luckily, Serbia got on the Schengen allow-list in 2009: I kept replacing my passports before expiration since I had no pages left.