Collocations for unpleasant - adj.

be, feel, look, seem, smell, sound, taste
become, get, turn
Things started to get unpleasant when the police were called.

make sth
He may make life unpleasant for the rest of us.

find sb/sth
I found the atmosphere in there extremely unpleasant.

extremely, fairly, very, etc.
decidedly, deeply, distinctly, downright, highly, most, particularly
His clothes smelled most unpleasant.

thoroughly
a thoroughly unpleasant man

not altogether, not entirely
The overall feeling was a strange mixture of sensations, not altogether unpleasant.

a little, slightly, etc.

for
tests which are unpleasant for patients

to
He was very unpleasant to my friends.

Unpleasant is used with these nouns:
character, consequence, encounter, episode, fact, incident, manner, memory, odour, reality, scene, sensation, side effect, situation, smell, stench, surprise, symptom, task, taste, truth