Laugh, trough, tough, rough. Maybe it should be "Vawfan"

Ghoul.

Hiccough.

Loughborough, which has it both ways. (Apocryphally pronounced by Australians as "Loogahbaroogah".)

augh is not as common as ough, but either one can make any sound in the whole syllabary.

How about Sequim, WA. Guess how to pronounciate that.

Or Puyallup, WA. Those two are definite shibboleth tests in the PNW.

Pend Oreille is the eastern WA test for western WA.

and for our eastern neighbours: Coeur d'Alene, Idaho (and Boise too)

My years of french class steered me wrong there.

Des Moines, WA vs Des Moines, IA.