His constant criticism was like a thorn in her side.
a fly in the ointment
Frequency:
65
%
The rainy weather was the fly in the ointment for their beach picnic.
a chip on the shoulder
Frequency:
60
%
Ever since he lost the game, he's had a chip on his shoulder.
a bee in the bonnet
Frequency:
50
%
She's had a bee in her bonnet about starting her own business.
Idiomatic Expressions for a burr in/under the saddle
Phrase: A burr under the saddle
Meaning: Refers to a persistent source of irritation or annoyance.
Usage: His constant complaints were like a burr under the saddle for the team.