[Learn] Status quo bias

Status quo - existing condition.
Bias - a preference or inclination, especially one that inhibits impartial judgement.

Altogether, 'status-quo bias' is a cognitive bias for the status-quo, where we are happy with the state of affairs that previously existed. It leads people to prefer things remain the same, or things to be altered only if is absolutely necessary.

Causes - It could be a result of loss aversion in the theory of decision making, which is referred to as a strong tendency of people in favour of avoiding losses instead of acquiring gains. Once the status-quo is established, it hurts for anything changes to occur.

Examples - A person signs up for a trial period of a magazine subscription, henceforth the person establishes a status-quo granting the ownership of a new magazine every week. Towards the end of the trial period, subscriber is not very likely to terminate the subscription as the value attached to the magazine by the reader is now greater. Loss aversion also comes into play. Let the possible utility gain of cancelling the subscription be £1  and a possible £1 loss in utility in cancelling, with same probability each. Loss aversion says that the £1 loss would make the person more dissatisfied than the satisfaction gained from the £1 earning. Therefore, sometimes we would not even make the 'right' choice if the potential gain is greater than potential loss (the decision would have been to cancel the subscription by a risk neutral individual).

Specific form of 'status-quo bias': Endowment effect - A hypothesis that people value a good or service that they own than the ones which don't belong to them.
An example could be seen by simply changing the magazine subscription above into something that you own. We value our belongings more than an identical object that doesn't belong to us. It gives us the same satisfaction, but we attach greater value to those that we are endowed with.

Effects - Theory of rational choice obviously plays an important role in decision making. We assume people select their most preferred items of choice in their preference/ranking. If we know this ranking, we can predict the choice infallibly. However, this assumption could be falsified in reality, as people adhering to their status-quo more often than they should.
Sticking to your guns could be bad for you. In a sense that it can lead people to become over conservative when faced with an unambiguously superior alternative. The strong desire to keep one thing (in order to avoid any loss making) could potentially yield greater loss. Say a bank offers a more favourable deposit interest rate, but one would be happy to keep the inferior banking account existing. Or say you are determined to change into a healthier way of living, but struggle to even take the very first step towards a healthier diet.
On the other hand, sticking to your guns can also be good for you. Status-quo bias plays a role in a daily routine. Once established, the routine would provide a safer path, and this self-reinforcing protection would encourage people to make safer choices.

All in all, this behavioural bias is often so subtle that people are not aware of it, making it extremely difficult to break out of a set of pattern. At the same time, nudging people into setting up a 'correct' starting point should be a good way forward.