Sometimes we suffer from to much imagination. We imagine things to be possible or feasible when they are not. We've long found it easy to imagine flying cars and colonies on the moon, but these things are incredibly difficult; too much imagination. While contemplating their lunar holiday, the very same people were unable to imagine women astronauts or cell phones; too little imagination.
Actual scientists say that we are systematically biased to think that both the past and the future look far too much like the present. I remember a computer nerd explaining to me exactly why there would never be streaming video on the internet. Being a nerd he was able to befuddle me with his impressive techno babble, but I remained confident that it would happen relatively soon. What he meant was that there were very good reasons why there was not streaming video 10 years ago (I actually also got this, since there was no streaming video around at the time). But it wasn't necessary for me to articulate how this would be done, I just knew that computers and the internet were getting faster, and there was no particular reason for this trend to reverse itself.
An issue I think suffers from to much imagination is consciousness. We find it too easy to imagine machines exactly like us (fancy robots) with life ambitions witty banter etc, which are not conscious. This is a problem because it means that naturalism is not true and one way or another, we're all naturalists (at least when we do science, I realise that this is usually a religious or spiritual issue).
So, how do we know when we're suffering from which deficiency?