For follow-up questions, from an askers point of view it could be quite difficult for them to tell what they should really be doing. What I mean by this is that a user could have a follow-up question for several reasons, such as (but not limited to):

1. The question they asked wasn't quite complete, and missed out some context; this doesn't change the question entirely, but does impact the solution(s). For example they may have omitted information on (some) edge cases.
2. The answer is actually just plain wrong, but the reader of the answer lacks the ability to identify that
3. The reader is in a "me too!" position, and failed to implement the problem properly
4. They genuinely do have a follow-up question; perhaps because they have implemented that solution and are now stuck on a latter (but related) part.

These scenarios likely all need different actions by the reader, and not all need a follow up question. Using the above number points, my expected behaviours would be

1. 1. Provided that the change doesn't significantly change the asked question edit the question to improve it and provide the missing context. If an existing answerer chooses to update their answer is up to them.
   2. If the missing context is significant, a new distinct question should be asked. (I've seen many times a user repost the entire question with changes, which often results in duplicate closer). The answers to the existing question should be judged on their attempt to answer the asked question (not the unasked question)
2. Downvote the answer (if able).
3. A comment may be appropriate. Follow-up questions, depending on the users attempt, can often result in duplicate closure as they don't actually link to the answer they tried to implement (incorrectly), and then get pointed back to the post that they failed to implement. Ideally, the user should cite the original answer, demonstrate their attempt and explain why it didn't work with a full MRE.
4. Ask a new question.

All of these different actions need good awareness of how the site, community, and curators work. If we do want follow-up questions (which I'm not against), I think that the user should be directed on being asked why they want to ask a follow-up, and this should differ depending on if the user is the author of the question or not. This means that the user might be directed to comment, or downvote, rather than asking a follow-up question. If they are directed to ask a follow up question, then a box like shown in Discussions in the new question, linking to the answer they were looking at, is important. If it's a "Me too!" question, they should also be directed to included their attempt, and explain why it didn't work, as this will help users see that their question is distinct enough. It could still be a simple error, but at least it's not a "I'm having this problem too, but the answer didn't work" type post.

This dialogue could be presented a little like the flags screen, and then leads to a (more) bespoke ask wizard, which includes appropriate prompts for the user to ensure that they demonstrate the relevant information, based on their follow-up question "type."

For follow-up questions, from an askers point of view it could be quite difficult for them to tell what they should really be doing. What I mean by this is that a user could have a follow-up question for several reasons, such as (but not limited to):

1. The question they asked wasn't quite complete, and missed out some context; this doesn't change the question entirely, but does impact the solution(s). For example they may have omitted information on (some) edge cases.
2. The answer is actually just plain wrong, but the reader of the answer lacks the ability to identify that
3. The reader is in a "me too!" position, and failed to implement the problem properly
4. They genuinely do have a follow-up question; perhaps because they have implemented that solution and are now stuck on a latter (but related) part.

These scenarios likely all need different actions by the reader, and not all need a follow up question. Using the above number points, my expected behaviours would be

1. 1. Provided that the change doesn't significantly change the asked question edit the question to improve it and provide the missing context. If an existing answerer chooses to update their answer is up to them.
   2. If the missing context is significant, a new distinct question should be asked. (I've seen many times a user repost the entire question with changes, which often results in duplicate closer). The answers to the existing question should be judged on their attempt to answer the asked question (not the unasked question)
2. Downvote the answer (if able).
3. A comment may be appropriate. Follow-up questions, depending on the users attempt, can often result in duplicate closure as they don't actually link to the answer they tried to implement (incorrectly), and then get pointed back to the post that they failed to implement. Ideally, the user should cite the original answer, demonstrate their attempt and explain why it didn't work with a full MRE.
4. Ask a new question.

All of these different actions need good awareness of how the site, community, and curators work. If we do want follow-up questions (which I'm not against), I think that the user should be directed on being asked why they want to ask a follow-up, and this should differ depending on if the user is the author of the question or not. This means that the user might be directed to comment, or downvote, rather than asking a follow-up question. If they are directed to ask a follow up question, then a box like shown in Discussions in the new question, linking to the answer they were looking at, is important. If it's a "Me too!" question, they should also be directed to included their attempt, and explain why it didn't work, as this will help users see that their question is distinct enough. It could still be a simple error, but at least it's not a "I'm having this problem too, but the answer didn't work" type post.

This dialogue could be presented a little like the flags screen, and then leads to a (more) bespoke ask wizard or advises the user on the "correct" action, such as "Please consider editing your question to include inforamtion on the edge case and leaving a comment to let the answerer know you've added some additional context". If they are sent to a question wizard it should include appropriate prompts for the user to ensure that they demonstrate the relevant information, based on their follow-up question "type."