This quote is from former Conservative British Prime Minister Maurice Harold MacMillan, 1st Earl of Stockton on February 24, 1984.

It's human nature to look upon a stranger with suspicion. The term "stranger danger" is one of the first things Children learn. But at some point, we have to learn to trust others. Trust and mistrust becomes a tightrope that we all have to walk. Being wary of others can be the key to protecting not only ourselves but also our loved ones. However, when you become too mistrustful, it can cause more harm and good. If you never let your guard down, others will find it hard to place their trust in you. 

So today don't be afraid to lower your defenses just a little. By allowing yourself to be vulnerable, you might open yourself up to healthy new relationships.