Endings
Some people’s endings don’t make sense. If you’ve been leading up to something the whole story, developing it etc, then don’t get to the end and make it a totally different, screwed up ending.
It just doesn’t make sense.
(Dedicated to Sgirl755 because she brought up this magnificent point in her rants book (with a great example) so you should go and check that out because that will probably give you some good tips!)
