the.com/irritate
To sand someone's patience down one grain at a time.
means To annoy or provoke mild, persistent frustration in a person, or to inflame physical tissue.
from From Latin irritare, to excite or provoke — the same root that made wool itchy and siblings unbearable for centuries.
Medical twinDoctors call inflamed skin literally irritated.
Low-gradeWeaker than anger, stronger than indifference.
Root cousinShares ancestry with irate, the boiled-over version.