Local attitudes toward tourists usually sit somewhere between genuine warmth and quiet fatigue, and which one you meet depends a lot on where you go and how you behave. In places where tourism is a lifeline, visitors are welcomed openly; in cities strained by overtourism, residents can be wary of crowds, noise and rising rents, and they warm up fast to visitors who behave like considerate guests.
A few sensitivities apply almost everywhere. Do not treat local life as a photo backdrop, especially religious rituals, funerals and children. Avoid loudly comparing prices, hygiene or efficiency to your home country. Dress with some modesty away from beach zones. Learn basic greetings, queue properly, tip or bargain according to local norms rather than your own, and be careful with jokes about religion, national history or politics, which often cut deeper than outsiders realize.
The visitors locals complain about are rarely the ones who make cultural mistakes; they are the ones who make no effort at all. Curiosity, patience and a little humility are understood in every language.