In the quantum world, tracking identical particles becomes impossible. So when one exchanges two particles in a pair, peculiar quantum effects emerge. For some particles, called bosons, nothing changes: their description is symmetric and, because of that, they feel a genuinely quantum attraction. Other particles, called fermions, behave differently instead: these pairs have an anti-symmetric description, which pushes them away when one exchanges their position. This intriguing behavior, which has nothing to do with our everyday life, is already at the core of powerful technologies.