My favorite page on WIkipedia is the List of cognitive biases, which I consider fundamental reading material for human life. One of the cognitive biases I'm personally particularly bad at compensating for is Escalation of Commitment, also known as Irrational Escalation. This bias is summed up well in the expression "Throwing good money after bad," where you put more money, energy or commitment into pursuing a particular outcome, despite having discovered that it's unlikely to pay off.
People do this because they know they've got a good chance of having wasted a significant amount of time or resources, but they might get it all to pay off (or even just mitigate their losses) if they just push it a little further. In doing so, they end up losing even more time/money/resources that they were in a fully conscious position to preserve.