1. When logic does not apply

2. Plot is thrown out the window

3. Usually instalove

4. When you don't care about quality over quantity

5. Communication? Ha, never heard of it.

6. Not particularly memorable

7. Follows tropes a little too closely

8. Huge power imbalance between couples

These novels either have one of these qualities or some to varying degrees. It's like junk food, cheap and provides instant gratification, but afterwards, you'll wonder why you even craved it. Anyway, these are all the criterion my sleep deprived brain could devise up for now, so, have a good night.