Like having your node process and propagate blocks quickly? That was Matt too (github.com/bitcoin/bitcoi…)
Wondering why you hardly ever see stale blocks any more ( )? Matt built FIBRE to speed up block propagation (bitcoinfibre.org).
Want to integrate lightning into your application? Matt's building rust-lightning to do that for you (github.com/rust-bitcoin/r…).
Matt understand Bitcoin better than almost anyone else in the world.
Without Matt generously giving his time and expertise, I wouldn't be working in Bitcoin open source development today.