Eternally glad I caught the Modoc and Siskiyou lines, and almost all SP branches in CA and OR (but not the Tillamook, darn it). Also lots of shortlines and industrial operations. My biggest tragedy has to be not seeing the Milwaukee electrics and hardly any of the MILW in general in the Pacific Northwest--although I did catch quite a few BN Fs and Alcos. My other great regret is not seeing the Rio Grande narrow gauge when it still had freight service, although I was a bit too young to be running off to Colorado before that ended. Still, I'm grateful for all those images of long-gone stuff packed away in all those little yellow boxes.