They happen when buying Jazz music. For a number of reasons:

- Jazz is such a varied genre. You can easily adore one jazz record but hate another. I think it is very love/hate.
- The artists changed their style all the time.
- The artists have ultra huge back catalogues with seemingly infinite song collections.
- Because the songs are instrumental, it's tough to remember ones you like titlewise.
- You often take the risk of ending up with some shit live recording from 1956.

I solved this today by asking this old man who works in HMV in Leeds. He got me some early John Coltrane. I never would have gone for Coltrane before because I heard the undislikeable A Love Supreme and found it to be not to my taste at all.

The moral of the story: ask the guys who work there.