I like playing along to the radio.
I don't mean trying to be not perfect, but seeing ho fast I can pick up the key and style, and how well I can anticipate the changes especially in unfamiliar songs.
I couldn't do this for toffee twenty odd years ago, but much better now - has helped give me the confidence to improvise/jam in a rock idiom which has already proven useful (nothing impresses a guitarist more than when you can play along without asking for the chords 🙂 they are easily pleased).