A lot of people get confused about where and how to use the colon. 

For instance, some people will place a colon after a verb to introduce things that follow, as in: "The four reasons are: greed, anger, stupidty and laziness." 

However, here’s a tidy little rule to remember:  Never use a colon after a verb, but do use it after a noun.

Let me rewrite the above example to show you what I mean:  "The four reasons are the following: greed, anger, stupidity and laziness."

Here, even though the colon is used correctly, you now have a wordiness and awkwardiness problem.

Solution:  Just take the colon out of the first sentence. 

(Also, I just contradicted myself by saying never use a colon after a verb when that’s exactly what you have to use to introduce a quotation of more than one sentence.  Example: He said:  "Blah. Blah."  Oops!  Anyway, don’t use it after are or include and other verbs that are introducing a series of nouns or thoughts within a sentence.)