Magic Spells: Specific Spells Are The Best

Magic is based on the all-encompassing energy, vibrations and power that surrounds every one of us, fills every one of us, and binds every one of us together throughout the day and night.
When you cast a spell, you use your conscious and sub-conscious minds to access that power. As a witch, you are able to manipulate, focus, direct and channel that energy using your will. Your intentions and desires are inherently connected to the power so when you change your desires, the power will react.
If you can focus your intentions very tightly with the aid of a good magic spells, the resulting change in the power and therefore your results - will be much stronger and more successful. So... why are specific magic spells better for success?
I've sort of explained it above. Basically what happens when you cast a spell is that your mind, your energy and your emotions exert influence over the universal power and energy and change it according to your will.
If you have a general thought in your mind, any changes you make will be very small. If you have a concentrated single goal, the changes will be much larger and so you'll get better results. The effort it takes to effect change in the world is often quite high, so if you think you can cause a big change very quickly and easily I'm afraid you might be let down. 
But, that doesn't mean you can't - it just means you have to make sure you have the right tools.
Think of it like this: imagine you took some bright red food colouring and threw it into the sea. Only a small amount, perhaps a teaspoonfull, perhaps a handful. As you throw it in, you expect the whole ocean that spreads out before you to instantly change to a bright shining red colour... and of course it doesn't happen.
The food colouring spreads itself very thinly throughout the entire ocean and so you see no noticeable difference in colour.
Now... imagine you throw the same amount of food colouring into your bathtub at home.. this time the bath will very quickly change colour to a shocking pink, showing your magic is working. This is because you're concentrating and targeting your effort so that no energy is wasted. You didn't try to change everything that was, you just tried to change a small particular part.
When you cast magic spells, the theory is very similar. If you have general intentions and try to cause a huge change, you will struggle. When you have very specific intentions and focus your efforts to cause a particular change, you will have more chance of success. It's similar to difference between moving a mountain in one go, or moving it piece by piece. The first is impossible, the second is definitely very possible indeed (although obviously moving a mountain takes a long time, your magic will not take that long!)
So, to summarise: when you're casting spells, specificity is best. This helps laser target your power to cause the proper effect that you desire. Since a magic spell is your tool for unlocking, unleashing and releasing your power, having a specific spell for a specific purpose will help you properly target your power, and therefore achieve better results!