The buzzing sound of the mosquito was a constant irritation during the night.
persistent problem
Frequency:
50
%
The leaky faucet became a persistent problem in the kitchen.
major annoyance
Frequency:
45
%
The traffic jam was a major annoyance on our road trip.
Idiomatic Expressions for bugbear
Phrase: A political bugbear
Meaning: A particular issue or concern that is a source of annoyance or frustration in politics
Usage: The lack of transparency in government spending has become a political bugbear for many citizens.