Satire is a use of language that involves mockery or ridicule. Sometimes the mockery is explicit; sometimes it is only implied.  In this paragraph, for instance, the mockery is implied rather than openly stated:

Recently I was looking through my little black book and I realized I didn't have too many friends. So I went out and got some Play by Justin Timberlake cologne and I put it on and now everybody likes me and I have tons of friends. An' then I took a look at my physique and noticed I was really skinny so I bought some Calvin Klein underwear and now I'm buff and get laid all the time. And I've always wanted to be more rugged, so I started smoking Malboros, and I like to be original so I got myself an iPad, and I could be more suave and debonair so I started making martinis with SKYY vodka and if I want to feel wacky an' zany I get my burger from Jack in the Box and I've never had a very positive attitude about life but my new Nike's keep me optimistic and now I'm a real go-getter. Anyway, now my life is perfect and I'm a much happier person. ("Just do it!") 

The speaker of this monologue is made to look ridiculous for a number of reasons, including the following:

• Few people are likely to like another person just because that person wears a particular kind of cologne.
• Putting on a certain brand of underwear does not in any major way alter one’s physique. Besides, the comment about being “laid” is sexist, demeaning, and shallow.
• Smoking cigarettes is ultimately likely to make a person less rugged, not more.
• Owning an iPad may or may not permit originality; there is no logical connection between the two.
• Drinking vodka does not make a person suave and debonair and may in fact have just the opposite effect.
• Eating a hamburger from any establishment whatsoever is unlikely to make anyone wild and zany unless the hamburger has been made according to some highly unusual (and possibly illegal) recipe.
• There is no logical connection between self-esteem and owning a particular brand of shoes unless one is a very shallow and materialistic person.
• No one’s life is “perfect.”
• Anyone who would be made happier for the reasons listed here is likely to be a fairly superficial person.
• The final comment (inside the parentheses) is completely unoriginal and thus reveals a lack of creativity.

This paragraph, then, is satirical because it reveals the speaker to be shallow, unintelligent, materialistic, illogical, uncreative, and sexually chauvinist. He also seems fundamentally insecure, despite his bragging here.  In other words, the paragraph reveals why he may be having trouble making friends in the first place.