Again, great business, but it can be a great business and...

Again, great business, but it can be a great business and overvalued on its fundamentals at the same time. Reading the comments I jotted down the following things (that I also suffer from / have suffered from) that have cost me money and now try to avoid:

-narrative fallacy (it's great because of x, y, z)
- familiarity bias (I know it, where else would I put my money?)
- recency bias (it's gone up in 'x' period of time)
- extrapolation fallacy (it's always been a great stock, therefore, it will continue to be a great stock forever)
- fear of missing out (it might go higher / I don't want to miss out on more gains / ive always regrettted selling)
- Nelsonian denial - (don't want to assess / even engage with the possible downside factors objectively because I like the good news better)
- inertia - (I've always held it)