Overconfidence is when a person's confidence in their judgement is much higher than their actual judgement. It makes us think that we can’t make mistakes, which ironically ultimately causes us to underperform.
Sometimes I do not study enough for quizzes due to believing that I’m already smart enough to know the material, causing me to get unwanted, and deserved, results.
The availability heuristic is when we make decisions based on an event's recency and vividness. This is a deadly sin as it causes us to fear the wrong things — only fearing what is currently being emphasized, even if something much more mundane is more dangerous.
When I watch videos of people gambling and they get good luck, this further enables me to gamble even if I previously decided I wouldn't.
Framing is when people's decisions are skewed by how something is presented, be it positive or negative. This is a deadly sin because it warps our thoughts and leads our beliefs to be affected by what words are used.
Hearing that there is a 1% chance of getting the highest rarity card in gambling is much more convincing than hearing there is a 99% chance of not getting it.
Memory construction is when our brain fits together puzzle pieces to construct our memory, false or not. Our memories are so fragile that we can actually fully believe that false, imagined memories are real, causing this to be a deadly sin.
Ms. Kitten saying that there were 19 reasons to love her class caused me to genuinely imagine another room to fill the gap of there actually only being 18 rooms.