Imagine you meeting someone new. You like the person, and you start fantasizing about a possible future of the relation. Maybe it’s a possible friendship, a person you'd like to do business with, or an old-fashioned romantic relationship. May you want to know if it's worth putting more energy into it.
If your mind starts to show you all the upsides and all the pleasure you had in that relation, it may be the right moment to reflect on the downsides. I experienced that in some way my mind tries to hide difficult and uncomfortable situations I had with that person.
A great human being once told me that if you're predicting a future with someone, make yourself conscious about the difficult situations you had together. Reflect on it.
If you found a way to figure out how to handle difficult situations with someone and live with the downsides of a person, it's way more likely that your relationship with last longer.