Fossilised Impressions
Many of us have very fixed mindsets, especially when it comes to judging things or people. We see or experience something, our mind takes a quick snapshot, and our conclusions are cemented in place. Changing it later would be a monumental task.
For example, I once ate at this Italian restaurant and the pizza we ordered was rather salty. Perhaps it was meant to be that way. However, nowadays whenever Celest mentions going back there, I immediately say "but the food is so salty" even though I am aware it is very likely that not every dish there is covered in salt. In addition, chefs change and recipes evolve over time - so a visit to the same place several months or years later could result in a very contrasting dining experience.
But I can feel my brain trying to tell me something different. It is hardwired to make the fastest and easiest decision.
The same is true when we assess people - although we know that humans can and will change over time, for better or worse. And also, we should give others a second chance in whatever situations they are in. But yet, the same things happen in our head when we see a familiar face, and our initial impressions jump to the forefront with little to no chance of a second evaluation.
But when you are aware of your first impression bias and understand that it could, and most likely would be wrong, you can reprogram your judgements to allow for new information to be gathered, and be open to re-experiencing this person.
Of course, some people don't change or evolve too minutely to make any impact. But still, it is important to give them a chance. After all, there might be people giving us chances too!