We have some strange low-quality flags most days, so I think perhaps a discussion on the best practice would be in order.
The Very Low Quality flag is intended to be used for posts that are beyond saving. Essentially, a VLQ flag says "This user is shitting all over the place and the post should be deleted immediately!" It is an offensive-lite flag, the "spam"-flag also incurs a reputation penalty and ban, when it is triggered on multiple posts of a user.
For a more comprehensive description please refer to Usage guide for very low quality flag.
If an answer is just not useful, i.e. talking about the right subject, giving good information, but just not really helping with the question it should be downvoted instead. – Don't worry about losing reputation for downvotes: When a post gets deleted due to accumulating downvotes your rep gets restored.
If an answer misses the topic completely, contains a new question, is a "thank you-statement", or a "have the same problem-comment", it should be flagged as not an answer.
What do you think, did I get that about right? Are some things handled differently on this SE?