1. I buy very close to director buying price

Just because you buy close to director buying price or below him doesn't mean you are not going to lose money. Unless you are thinking 'You jump, I jump'

Yes the director own shares in the company, maybe those investments are only 5% of his total portfolio, while you have 50-100% of your portfolio in there. Or maybe the director is looking 10-20 years ahead on those investments, while you are looking at 4 weeks ahead.

When the stock price kaput, if you have 9 lives, you will be dead 9 times, the director will still be hype and alive, it is just a bruise to the director.

2. This and this fund hold stakes in the company

Similar to above. Large investment funds, be it government or private, prefer to diversify their investment across many stocks to reduce volatility. 

Yes it make sense to think and ask why would they invest in them. However it is foolish to buy a stock just because some famous funds had stakes in it. Do you know why they bought it?

Maybe they again have a 10 years plan, or maybe it is part of a strategic alliance for the fund in order to have access some key resources in the company, rather than making profit from the share price? 

3. The price cannot get any lower, 0% downside, unlimited upside

Many people mentioned this when they are holding MAS because they are confident the government will not let it fail. I feel sorry if your average buying price is anything between 30 cents and above. That's pretty much everyone. 

You guess it right, the government is unlikely to let it fail as per current development (Khazanah to privatize MAS), but no prize for you for getting it right. 

It is also one of the justification or mentality for people buying penny stock, because it feels 'safer' to buy a 30 cents stock than a RM30 stock. However that is always further from the truth, penny stocks are almost always more volatile and consist of companies that has smaller market cap and money losing, although there are exceptions. 

4. The stock has gone up, so I am right (brag on forum)...The stock has gone down, so I am wrong

IF you haven't read the post I wrote about skills and luck, read here.

Investing consist a mix of luck and skills. You can be right, just like you can guess correctly in coin flipping for 7 consecutive times, but that doesn't mean you are skillful, you are just lucky. Vice versa, the opposite happens doesn't mean you are wrong either.

Focus on the process not the outcome, improve your stock picking skills, the outcome will take care itself.

5. It's always darkest before the dawn 

Similar to point 3, many people buy into the hype of turnaround stories, because they are exciting and juicy, and if you are right, luckily right, you can make tons of money from it. But turnaround rarely turn, and if they do, perhaps many years later. 

If you are not skillful (many people like to think they are different), stick to well-run, reputable, money making companies. Investing in companies with a record of losing money needs a lot of skills, or if you rely on luck, your luck will eventually run out. Why? Reversion to the mean, reread point 4. 

6. This is the hottest trend/stocks in town

Normally certain stocks become hot because there are rumors they going to win some big contracts, or already have won. Or sometimes there are some big prediction from analysts like Oil & Gas Industry post election, or Plantation Industry this year because of El Nino, strong demand, short supply etc. 

It is certainly good news they won contracts, but the project haven't even started, cash haven't even trickle in, you are already projecting how much EPS going to be for next few quarters or years. Not to mention, when the news are out, most are already priced into the stock. If the company makes more money as expected, share price stays there. If anything below expectation, you are dead.

Same for plantations stocks this year, the hype has been priced in, thats why most plantations stocks are trading at PE 25 and above, if they deliver good results, all good, you don't make much money. If they fail because CPO price is lower or operation expenses are higher, margin is lower or combination of all, you're done.