Curling the index finger, or four fingers toward you as a gesture of inviting somebody to come closer, can be mistaken for ‘good bye’ in southern Europe. In Philippines and East Asia, curling the index finger is used only to beckon dogs.
Pointing directly to someone or something using index finger in Europe is considered impolite. In China, Japan, Latin America and Indonesia it has very rude connotations. In many African countries, the index finger is used for pointing only at inanimate objects.
Gestures can say more than words, and just as we are usually very careful when using foreign languages, we should consider carefully what hand gestures we should display whilst in different cultures. The world is indeed full of diversities, so enjoy your learning.