Was there any investment decision you made which you regretted till today?

No dont have

Regret is investing in sg market

Blindly following ideas. Sometimes I come across articles / reviews by people and just blindly follow their ideas due to my laziness in conducting my due diligence and I think that showed itself when stock prices start falling and the only person I feel like blaming is the person who I followed. But in reality i only have myself to blame.

So, never be lazy when making investment decisions

Yes, not cutting my losses and taking profits.

When I started trading/investing, I did not use stop-loss because I held on to a hope that the security's price would move in the direction I want. But boy, I was wrong most of the time and ended up losing all my exposure on them. Thankfully, my exposures were 1-2% of my portfolio, so I was able to digest the loss.

Similarly, I also did not take profits when I should have, instead waited for the profits to soar.

Emotions have no place in trading.