Influence is a great book (and a fun read).
Although the author himself marketed it that way, it's a lot deeper than just "parlor tricks" to get you to buy stuff.
It explains fundamentally why some people may listen to you and others may not (and vice versa). As someone who was always a poor influencer, I always wondered why if I explained something to someone, they would reject it. But if someone else explained it in the same way, they would accept it. The book explains why really well.
Overall, if you do not conform well to societal norms (that includes being a geek), it will explain why your life will be miserable.
It explains why people can be persuaded to do crazy things like committing suicide for a cult (and why others won't do such things).
It also explains the power of reciprocity (as well as its down side). It starts with a simple story: The author was walking down the street when a kid tried to sell him a chocolate bar for $2 for some good cause. The author doesn't like chocolate, and it's too expensive. The kid then says "OK, I'll give it to you for a dollar!" The author, kind of automatically paid him a dollar and took the chocolate. A few minutes later, he wondered why he bought it: He doesn't like chocolate and doesn't care about the cause! The reason was reciprocity: The kid made a concession, and he automatically felt a need to reciprocate.
This is a common tactic in negotiations (and one negotiation training often warns you about), so you could view it as a parlor trick. But it does go deeper.
Many people in my life have gotten upset with me because:
1. They would have a request of me that I do not want to grant.
2. They offer me something for it - something I do not care for.
3. They make concessions on things or offer me more - again for things I do not care for.
4. They then get upset at me that I'm selfish, look how much others are willing to do for me and I don't reciprocate, etc.
But, umm, why should I reciprocate for something that is of no value to me? These people are not trying to manipulate me - this is their true feeling. Humans are hard wired for reciprocity, and when you don't play along, people can get upset.
I once asked a friend to do some exercise with me. He agreed, but when the time came he really didn't want to do it (bad weather). He said "Hey, tell you what: I'll do this for you if you learn skill X" (skill X is something I've been avoiding for years.
To me, learning skill X is a huge investment I did not want to make, and certainly not worth doing just to get him to exercise with me that day. So I decided to release him from his obligation. I declined his offer and said it's OK if he doesn't want to work out with me today.
Over a year later, I discovered that had upset him. From his perspective, he was willing to make a big sacrifice for me (work out with me that day with poor weather), but I was not willing to reciprocate. I had to explain to him: It was a big sacrifice for him, but only a small gain to me (it wasn't too big a deal if he didn't work out with me). Fundamentally, I do not need to reward him for making a big sacrifice, if I do not value it. I released him precisely because I sensed it was a big sacrifice, and did not want him to waste it.
Negotiation training teaches you this: If you want to make concessions, ensure they are meaningful to the other party. And on the flip side, be wary of concessions others make for you - if you do not value them, signal this strongly to the other side.
I may understand this, but most of the world doesn't. They will make concessions that have no value to you, and much of society will expect you to reciprocate. It'll take a lot of zen-fu not to get yourself in these situations.
tldr; Sorry for the lengthy comment. Book worth reading. And oh, I have only read a third of it...