Why you should teach your dog tricks.
Reason #1: Because it's fun!
If you are doing it right, your dog will love it, and you will have something fun to show off when the guests arrive. Let's face it, having a dog that will roll-over, and give paw, and will spin or "sit pretty" is fun. It has a certain effect on people, and smiles begin to pop up here and there with the simplest of tricks performed by our faithful companions.
Reason #2: Because training your pup is a bonding experience for both of you.
It's important to develop and maintain a certain level of closeness with your dog, and training gives us a very simple structure to do that. Hopefully, the methods you are using engage your pup in a positive way, and they look forward to your training sessions, as if it's playtime.
Reason #3: Because it will help you with focusing your dog, if the need arises.
If you are planning to have a dog that is a true companion, and is coming with you everywhere you go, sooner or later you will be in a situation where the two of you either waiting for something (in line?), or maybe approaching a situation that will be a known source of anxiety for your pup. Having a number of tricks under your sleeve will help you to take your dog's mind off the trouble, and will keep his mind busy in a positive way.
Reason #4: Because if you have "a scary" breed, it helps people get over their fears.
Let me tell you something, very few people keep a straight face when my Rottie rolls-over on command, and begs for a belly rub. It breaks the ice, and when you own certain breeds - it's a no small matter.
Reason #5: Because it reinforces the fact that you lead and they follow.
If your dog can perform a variety of tricks, you can easily follow NILIF method of raising a dog, and it sets up for a well-balanced dynamic in your family, where the dog listens to people, and not the other way around.