My Nikon D5000 delays in taking pictures?

I'm an Ametuer photographer, and I have a Nikon D5000, I've had it for about 2 years now, and it seems that when I'm taking pictures it takes a long time for the camera to actually take. I'm getting frustrated with my camera because I've missed So many great facial expressions and perfect moments because my camera wouldn't take the picture. I don't understand why. Is it a setting on my camera? Maybe, something to do with the lens? I've used friend's Cannon cameras before and they don't do this, I'm considering switching brands, but I've got so much money invested in Nikon, I don't want it to be a waste.

Check that the 2s delayed action is turned off.

You are putting your images onto computer (and formatting your card afterwards) at every opportinity aren't you?

Don't use Live view. When you choose that horrible option, you cause the camera to delay snapping the image. First, you'll have the camera on live-view. Then you have to press the shutter to get the camera to autofocus. Finally, you'll have to press again to snap the image.

It's not the camera. Most of the time… Http://keerok-photography.blogspot.com/2012/11/you-need-more-light.html

If you are shooting under lots of light and the camera is still slow, make sure it is set to Auto mode, Auto ISO, Auto white balance, AF on and EV at 0.

http://keerok-photography.blogspot.com/2012/10/learn-photography.html

If the camera doesn't work properly in Auto mode under lots of light, bring it back to the store you bought it from and ask for service.

What speed memory card are you using? If it isn't a class 6 or class 10 it might not be fast enough.

Is Automatic D Lighting switched on? That can slow down picture taking.

There's no point in switching brands. My wife's D5100 is really quick.