The piano pieces from Béla Bartók's For Children (1909) and Mikrokosmos (1926/39) were among the first I played as a boy. They introduced the pianist to compositional technique as well as piano playing skills. I got used to 20th-century harmony.
Later at university we did detailed analyses of Bartók's Music for Strings, Percussion & Celesta (1936) and I listened to his Concerto for Orchestra (1945), 44 Duos for 2 Violins (1931), The Miraculous Mandarin (1931) and his String Quartets.
Writings on Bartók describe how he used parlando rubato folk style Fibonacci sequence, golden section, prime numbers, symmetry and opposing tonalites. These observations sometimes affect my music.