I've long been a fan of shows such as Classic Albums where you get to see how songs are constructed . It interests me to hear the artists taking you through the recording process and to hear how certain parts sound isolated on the desk.
On Youtube there's plenty of classics to check out. You get a chance to hear the true skill of what's written and played by the musicians and of course some bits are often hidden far down in the mix of the final track especially bass parts. Even the upfront guitar parts reveal a lot of the tone when standalone.
The Who's John Entwistle's Bass part on Won't Get Fooled Again
Paul Kossoff - Free- All Right Now I've started this at 1.43 to get a bit of the main riff and the part leading into the solo. Great stuff.