Explanation
In the United States, beckoning someone with your index finger can be seen as condescending or demanding, especially if done abruptly or in a formal setting. It is generally acceptable among close friends or in casual contexts, but in professional or public situations, it may be perceived as rude or disrespectful. A more polite alternative is to use a hand gesture with all fingers or to verbally invite someone over.
Local Tip
Instead of curling your index finger, use an open palm with fingers together and motion toward yourself, or simply say 'Could you come here, please?'
How it compares elsewhere
Beckoning with the index finger is highly offensive, as it is used to call animals; use a wave with all fingers pointing down.
Beckoning with a finger is considered very disrespectful and may be seen as a challenge; use a gentle hand wave with palm down.
While not as offensive as in some cultures, it can still be seen as abrupt or informal; a verbal request is preferred in formal settings.