As my career has progressed, I have noticed that my best work comes from when I constantly step back and take a pessimist's view of the solution. Through this lens I am able to find potential pitfalls that I otherwise would have missed.
I remember a recent brainstorming session at work where we were evaluating a potential technical solution for a client. This solution was going to entail a pretty large change to a legacy system. As a result, we wanted to list out the different pros/cons in order to make sure we had our bases covered.
As we went through the list --ranking items 1-10 on various criteria-- we felt really good about this new solution. "Cost savings: 7". "Scalability: 9", "User Experience: 9". And on, and on.
Once we removed our blinders and gave the list a final once-over, we noticed a troubling trend. All of our criteria went from 5 and below on the legacy system to 7 and above on our newly designed system.
Upon simultaneously realizing what just happened one of my team members summed up our naive efforts: "This list activates my are you kidding me?! response. There is no way anyone would take this seriously." And, he's right.
Being an optimist at heart I am quick to think tasks will take a shorter amount of time then they actually will and functionality will provide a higher benefit than it might. These default urges must be quarantined when working on a project and I've found the best way to do this is to constantly take a step back and look at things like a pessimist would. This tactic helps ensure you aren't sugar coating or glossing over important issues in a way that looks like you have something to hide or (worse) don't know what you are talking about.
Being an optimist is great, just make sure you take the time to view your work through the vantage point of a pessimist before you are finished. This could save you countless headaches in the future.