To me, CCR was and is a prime example of one of those bands that's "better than you think." To be specific, "despite being played to death on the radio they were actually remarkably good, even great." One of those. In order to recognize their worth, I had to try to listen to them with (at least partially) fresh ears. Discount all the times I've heard them on radios and at parties, discount the phony/hokey sounding lead vocals, and just zero in on the tight song structures, economical guitar solos, the rock'n'roll grooves and catchy melodies. Once you manage to do that though, you realized that they churned out a hell of a lot of good songs, no way around it.
And trying to mentally step back and listen to anything with fresh ears is a very useful exercise.