Halliday & Matthiessen (2014: 273-4):
Within the semiotic domain of attribution, there is one variety of ‘attributive’ clause in which the Attribute denotes a quality of sensing equivalent to the Process of a ‘mental’ clause. … ‘Relational’ clauses with a quality of sensing fall into two types: those which match the like [‘emanating’] type of ‘mental’ clause, with Carrier equivalent to Senser; and those which match the please [‘impinging’] type of ‘mental’ clause, with Carrier equivalent to Phenomenon. … many of the Attributes are evaluative in nature; this type of clause is an important grammatical strategy in the enactment of appraisal.
For example, from Yes, Minister
Jim Hacker: I'm a curious person. [Carrier equivalent to Senser]
Sir Humphrey Appleby: You certainly are, Minister. [Carrier equivalent to Phenomenon]