It's generally a good thing to be observant. In fact, we even have a saying: 'Look before you leap.' Some people are by nature more perceptive than others, but observational skills can be learnt. However perceptive we think we are, there are times when it may be a good idea to take a second look. I have often been surprised when I have looked twice at things. Perhaps what I thought was a red car was actually blue; perhaps there were three people rather than two. Often it really doesn't matter too much if we misperceive in this way, but sometimes it does - it may even be a matter of life and death. So, when you know that it's important - take a second look!