Collocations for irritating - adj.

be
The sheer number of tourists can be irritating.

become, get
The song gets a bit irritating after a while.

find sth

extremely, fairly, very, etc.
highly, intensely (esp. BrE)
I find all this highly irritating

a little, slightly, etc.
mildly
I have always found her mildly irritating.

downright (informal)
His voice is downright irritating.

Irritating is used with these nouns:
habit, mannerism