|In these constructions the verb following who or that should be plural to agree with the antecedents those or things:
defacing books is one of the things that really bother me
he is one of
the 30,000 young people who pack a suitcase and head for London
those archetypal Londoners who seem to have stepped out of Mary Poppins
The logic of the plural can best be seen by turning the sentence
Of the things that really bother me, defacing books is one.