I'm a big buyer of romances. I pick them up on amazon and on ebay, occasionally in the few remaining on street book shops and fairly frequently in charity shops (thrift stores, I think, if you're Stateside).
All too often, I find my charity shop purchases make their way back to the charity shop having left me with a feeling of disatisfaction. Clearly their original owner had ditched them too, leaving them to drift from home to home unloved and uncared for. Which has left me wondering - what makes a keeper? And is one reader's keeper, another's poison?
For me the top five are probably:
1. Conflicts that could be sorted out merely by having a conversation, when there is no good reason for them not to share. It has me feeling tense and wanting to shout "just SAY it!" - and not in a good way.
2. Dialogue that sort of makes an effort to be historical, but either gets the era wrong (sounds 1920s in the 1820s) or sounds so clunky you want to cry. How is it Georgette Heyer could manage scrupulously observed regency vocabulary and still keep her conversations lively and flowing, but other people turn into a hideous parody of a BBC costume drama?
3. Heroes that are so unlikeable and humourless that the heroine should either just whack them over the head or take herself off to a therapist to ask why she is persisting. A bit of humour goes a long way... actually come to think of it, that applies to heroines too!
4. Over veneration of naivity, innocence and purity in a heroine. Other people might find that sweet - I just want them to get a bit of gumption. Or maybe I just don't identify with angels. Georgette Heyer was onto that - why do you think Frederica and not Charis was the heroine, in the novel of the same name?
5. Two dimensional characters - see points 3 and 4 for examples!