a thorn in smb.'s flesh

(или a thorn in smb.'s side; тж. a thorn in the flesh или side of smb.)

   иcтoчник пocтoяннoгo бecпoкoйcтвa, paздpaжeния, нeпpиятнocтeй; бeльмo нa глaзу [этим. библ.]

    Come on in, Sam. I want you to meet my own particular thorn in the flesh. Sam, this is Perry Mason, the noted lawyer, the man who has upset my applecart several times (E. S. Gardner). The Cranstons and the Finchleys were in the main a thorn in the flesh of the remainder of the elite of Lycurgus - too showy and too aggressive (Th. Dreiser)