Why noble gases have positive electron affinity?

Noble gases typically have zero or very low electron affinity because their outer electron shells are already full, making them stable and non-reactive. However, in specific cases, certain noble gases can exhibit a slight positive electron affinity due to the potential for electron-electron repulsion when an additional electron is added to the already filled shell. This results in a situation where the energy required to add an electron exceeds any potential stabilization, leading to a positive value for electron affinity. Nonetheless, this phenomenon is rare and not characteristic of all noble gases.