Ask a room of expats anywhere for their biggest daily struggles and the same handful surface, just in different proportions per country. Bureaucracy usually tops the list: permits, registrations, banking and anything official consume energy in most countries, compounded when it all happens in a language you are still learning. Language itself is the second, less for dramatic moments than for the daily friction of pharmacy visits, school notices, tax letters and small talk, and it feeds directly into the third, social isolation, which peaks somewhere in the first year once novelty fades and the depth of friendships back home has no local replacement yet. Cost of living stings in the expensive hubs, especially housing, and in cheaper countries the challenge inverts into navigating different standards and systems. Add the quieter ones people mention late in the evening: distance from aging parents, careers of accompanying spouses, children's transitions, and the strange fatigue of every simple task requiring thought.
None of this is an argument against the life, just its honest price list, and every item has known mitigations: language classes and repetition-based socializing for isolation, systems and local help for bureaucracy, expat communities for the knowledge gaps.
Most long-term expats describe the same arc: a hard first year, a turning second, and a settled third in which the challenges become background rather than headline. Knowing the arc in advance is itself half the protection.