How reliable are computer models?

We live in a time with so much technological services to our expense that we don't know what to do with it all. There are new advances in technology every day, and I think that we have gotten to the point that we take it for granted. Even computers themselves are completely amazing. We have a little box that can do so many things that would be unimaginable otherwise. The fact that the internet exists is extraordinary - we can communicate in a many to many fashion, and there is a link between people all over the world! But still, we complain that our internet is too slow, the video quality is too poor, and all sorts of other things that we would not be even within the realm of possibility a few years previous. I think comedian Louis C.K. sums it up pretty well in the viral YouTube clip:

So, things such as computer models which are currently used to predict trends such as stock market prices, weather forecasts, earth plate shifts, these are all made possible by such technological advances previously mentioned. While they are not completely accurate, we have no right to complain about their efficacy, because the mere fact that they exist is a blessing, and by depending on these services 100% just shows our own dependence on technology.We should learn to appreciate these services and understand their limitations, rather then become angered that they are not "good enough." We must consider the fact that these computer models are able to predict certain trends to a certain precision and realize that even if they are not perfect, they are better then nothing - which is what we had before!