Pianotec Stage modelling software and discovering the magnificently rendered range of keyboard sounds available. I am finding it hard to be bothered playing my U3 now that I have connected up the laptop to my Yamaha 88 note weighted synth to enjoy a panoply of options ranging from clavichords and harpsichords, fortepianos, uncanny sounding classic electric pianos rhodes/clavs/wurlys and a classic grand in Pianoteq's modelling of the Steinway D. Many of these models have a variety of different iterations and extraordinarily, some of these great keyboards are available as free add-ons.
I have gained a much better appreciation and understanding of the music I have been playing recently. Bach on a harpsichord or clavichord suddenly takes on a whole new guise and playing one of Beethoven early sonatas on a Graf piano is a sublime experience. I don't currently play any Chopin but I can imagine it would be rewarding to do so on a Pleyel. You can try Pianoteq out completely free with all the sounds albeit with a restricted range of notes and for 20 minutes at a time before having to close and restart to keep playing.