Okay, here goes.
1. I'm assuming you already have at least a few other pairs of speakers. Instead of buying another pair, try to relax and enjoy the ones you already have.
2. If you have a wife who insists you already have enough stuff, remember: family first, speakers second.
3. Be lazy! Do you really want to have to get up from your comfy chair, go in a car, turn the car on, drive all the way to where the speakers are, turn the car off, get out of the car, load speakers (which may be heavy) into a car, turn the car on, drive all the way home, and unload the speakers? That's a lot of effort.
3b. Think about the environment! If you drive to get the speakers, you're polluting the environment slightly.
3c. If you don't drive, you'll have to walk. Again with reason 3a, only more so.
4. If reason 2 is true, your wife may be so upset about the mountain of speakers in your house, she may throw away a pair of speakers without telling you. So now, by buying speakers, you'll actually have less speakers.
5. The country is in a recession. Instead of spending the money on yourself, treat a hobo to a hamburger and milkshake at McDonalds.
6. How do you know you're only buying those speakers? Maybe the seller recently "upgraded" to a Bose or Walmart speaker system and will make you listen to the system when you come to visit. If you're buying them from a store, maybe someone will try to rob the store while you're there and then you'll have to take time out of your busy schedule to serve as a witness at the police station.
7. There are many other nice people at AudioKarma who would like to have those speakers. So let someone else find a good audio deal this time.
8. For every good deal you get on a speaker system, 17 more people buy Bose.
9. The speakers are infected with deadly bacteria for which scientists have not yet found a cure.
9b. The bacteria multiply every time music is played through the speakers.
How's that for reasons?