Some things that are especially applicable, especially when I am so damn tired my body is aching, despite my having done nothing physical at all. 

1. I do not suffer fools. Do not ask me dumb questions, especially if it is work-related. Do your very, very basic Google. The more tired I am, the worse my temper. And I do lash out. Not personal attacks - never personal attacks - but '?' becomes '??' and I will start explaining basic concepts to you like you are a child, because evidently. 

1-1. However, I will never raise my voice at you, and if you are polite or start with 'sorry', I will be appeased. 

2. If you are not clear/do not categorise your question, I will have to do it for you, and there is no way for me to do that without making you look like a fool. Seriously. If you ask me 'why is x happening this way and also x is starting at 1000hrs and that doesn't make sense and why is that, but that must be helpful for x happening this way', I will kill you in my head 1000 times. 

2-1. This happens in all areas of life. I don't understand it. How will you get the answer you need to the questions you have, if you do not even have a clear question? Did you not care about your question to begin with? Then why ask? 

I don't believe the world is filled with idiots. I think people must be too lazy, or maybe they just don't care enough. 

Tough, I do care. 

Separately, I have never been as happy as when I said, in a nicer way, 'please don't talk to me, I don't think I want you in my life'. And I have also been extremely happy when I said 'hey when are you free? :)'. In other words, I'm drawing boundaries. It's scary, because some people argue or get mad because their ego is hurt. But in general, I think my life is better for it.