The list.

List as of may 1st 2017

1 Don't ask a barber if you need a hair cut.

2 The Second Law of Thermodynamics. ( see here.  www.livescience.com/50941-second-law-thermodynamics.html)  This is still my favourite. Though the 1st is also quite good.

3 Everything is more complicated than you think it is. (see Rule 2 )

4 The more money, time or effort someone puts into selling you something the less likely you are to really need it.

5 Human Beings are fundamentally good. (despite all the evidence to the contrary. See rule 3 )

6 Never Post Angry. NPA. ( for "post"
read Email, Text, Converse, Argue ).

7. You are not as clever as you think you are. ( for "you" read "we".  And make the appropriate mental changes to the Grammar)

8. Probably best to do your laundry when it is raining.

9. When endeavouring to do something creative, let it happen. Don't force it.

10. Never trust a headline with numbers in it.

Any headline with a number in it is a bad headline. In that it is probably wrong at a very fundamental level. 

11.Sarcasm does not work on the Internet. This is particularly true in the comment section.  Unless you are very careful with it's use. Or your readers are particularly intelligent.

there will be more someday.... see rule 9