One of the things that's confusing about tags is that tags are tools to help people find questions they can answer. This means that there can be situations where the two tags accomplish the same purpose, even though the definitions of the words used in the tag name may be slightly different.
This site has four tags--rudeness, politeness, etiquette, and courtesy--that should be combined into two tags: politeness and etiquette. Even though the words rudeness, politeness, etiquette, and courtesy have different definitions, these tags are being used for two categories of questions, not four. Let's take a look at some of the questions in each tag to get a better idea of what's going on.
- How to tell someone that they are eating with their mouth open? -- This is a question about someone doing rude, e.g. "eating with their mouth open". However, the actual question asked--how can I politely ask my girlfriend's mother to stop chewing with her mouth open.
- Should I monetarily reward the person who found my phone? -- this question doesn't actually need the rudeness tag: it's just about what to do in a certain situation. Nobody is being rude here, the OP is not specifying that they need to be polite, etc.
- How do I continue to be quiet without being rude? -- the OP assumed that they were being rude by being quiet, but that assumption isn't necessarily correct. The actual question is about how to improve and be more polite. (This question should be closed because the OP hasn't given enough information for us to give them good advice, but that's an issue for another day).
- Is it rude to post on an English site when my English needs a lot of improvement? -- asking if something is rude.
- Should I always ask a dog owner before I pet their dog? -- this is just a question asking about what someone should do. It's not clear how politeness enters the equation, this is a question about what to do, not how to do something politely.
- How can I ask a possible long-lost relative to prove his identity? -- how to ask someone to do something (confirm their identify) politely.
- How do I decline conversation in my native language? -- how to do something politely.
- How do I decline conversation in my native language? -- also tagged with politeness. This is a question about what someone should do in a certain situation. One definition of etiquette is a set of rules about what to do in social situations.
- Is it rude to offer my seat up on public transit to someone who is much older than me but not yet a senior? -- about what to do in a certain situation.
- Arguing science with a passionate non-scientist? -- about what to do in a certain situation.
- Inquiring about a colleague's retirement plans without seeming to be rude? -- about how to do something politely.
- How can I politely make an offer on a used vehicle? -- this is about how to do something politely.
- Inquiring about a colleague's retirement plans without seeming to be rude? -- about how to do something politely
- Does a greetings card require a return in kind? -- a question about what to do in a certain situation.
Looking at these questions, I see two categories of questions, not four:
- Questions about how to be polite, how to do something politely, and what the polite thing to do is.
- Questions about how to do something by following social norms.
Let's do a cleanup and merge these tags.
Someone argued that rudeness should, in theory, be used for questions about interacting with people who are rude. That of course is not how rudeness is being used, and trying to get people to change how they use a certain tag is a lost cause: people don't read tag wikis and won't respond to your attempts to edit questions and get people to change their usage. (I've seen people spend days on this and it never works). The other problem with this is that a tag for dealing with rude people already exists: it's difficult-people. We're already using difficult-people; let's make things simple and keep using it.