Sheldon Cooper, “The Big Bang Theory” breakout character, is the most famous geek ever. He is extremely intelligent but totally lacks social skills.
Listen to Sheldon’s intonations.
The tone of his speech and stresses in sentences show his inability empathise and makes him unpleasant to others, even to the closest friends.
Sheldon is a native speaker of English still people find it hard to interact with him.
Imagine how hard it is for people to interact with a non-native, if intonations are misused.