Why don't some people respond to their emails?

[IAMME]

Why don't some people respond to their emails? Are they just being rude?

[Sarah]

I guess they're rude people. Honestly, I do this a lot. I just don't want to talk to some people.

[Shadohz]

As one of those 'rude' people I'll give you a list of reasons why:
Co-workers-
1. You annoy me.
2. You email me about trivial problems that you should be able to fix yourself.
3. You were too lazy to look for a solution to a problem.
4. I'm busy with a project that's more important than your email.
5. You're using email to circumvent an established communication protocol (e.g. you're supposed to contact my manager or another team about a problem, but you contacted me instead because you knew I could fix it or fix it faster than using normal channels).
6. Your email is more important to you than it is to me.
7. My response to your email could get me fired.
8. I really, REALLY don't like you, but you choose to email me anyway behaving like a troll so I add you to block.
9. I have all your emails automatically moved to a specific folder so I haven't read it yet or missed reading it.
10. You are a high-output team (i.e. your team sends out alot of emails regarding things that don't affect my daily work). I ignore these type of emails by default.
11. You email is too long or wordy. I don't understand what you're saying or you need to dumb-it-down to speak in a language I can understand (i.e. don't speak in accounting jargon when speaking with a tech).

Family -
1. I really, REALLY don't like you.
2. I have other things to do.
3. You could've contacted me by phone instead of email.
4. I'm busy.
5. I'm at work and don't have time to deal with 'personal' matters.
6. You always ask me 'did I get your email' after I've already read the email but didn't have time to respond.
7. You spam my inbox much too often.
8. You've been blocked and I didn't tell you.
9. I want you to find another form of communication (in some forms, not at all).
10. I don't want my response to come back to haunt me.

[Boss]

Because they think it important.