The song that made me unlock new techniques while I was only playing acoustic was "Che Rumore Fa La Felicità" (link): it forced me to learn to play percussion while finger picking and it's a thing I keep doing years later, even if I play rhythm on an electric (finger picking + percussion on a Telecaster middle position is among my favourite guitar tones).
If we're talking about music theory instead, playing on a ukulele will force you to own your triads positions and escape the CAGED system (pun intended).