Adjective patterns with what
Pattern 5: what v-link ADJ to n v-link that/wh
The adjective group is followed by a prepositional phrase beginning with to. Adjectives with this pattern indicate that something is important or interesting. The noun group following to indicates who thinks it is important or interesting.
amazing fascinating important interesting
What was interesting to me is that they are not drawing such a strict age line as I thought they might.