Question

In human relations, the irritation threshold is the

Answer 1

the point at which a person notices something and becomes annoyed

Answer 2

In human relations, the irritation threshold is the point at which a person notices something and becomes annoyed.
This threshold can be quite different for different people - some people may have a really high irritation threshold, meaning that there isn't much that could annoy them. On the other hand, some people can become annoyed with the littlest things - it really depends on a person.