Paul Graham in his essay writes, "The world of investors
is a foreign one to most hackers—partly because investors
are so unlike hackers, and partly because they tend to
operate in secret"

The top 20 or so points that he highlights are:

1. The investors are what make a startup hub.
2. Angel investors are the most critical.
3. Angels don't like publicity.
4. Most investors, especially VCs, are not like founders.
5. Most investors are momentum investors.
6. Most investors are looking for big hits.
7. VCs want to invest large amounts.
8. Valuations are fiction.
9. Investors look for founders like the current stars.
10. The contribution of investors tends to be underestimated.
11. VCs are afraid of looking bad.
12. Being turned down by investors doesn't mean much.
13. Investors are emotional.
14. The negotiation never stops till the closing.
15. Investors like to co-invest.
16. Investors collude.
17. Large-scale investors care about their portfolio, not any individual
company.
18. Investors have different risk profiles from founders.
19. Investors vary greatly.
20. Investors don't realize how much it costs to raise money from them.
21. Investors don't like to say no.
22. You need investors.
23. Investors like it when you don't need them.

Read in detail at
http://www.paulgraham.com/guidetoinvestors.html