Why

- Aiyah, Yesterday brought at RMX.XX, I earn RMX.XX liau.
- Aiyah, Why I buy, it start to go down? Should I cut lost/sell? Should average up?
- Aiyah, Why I sell, it start to go up? Should I buy back?

Don't chase.
Set your target, then you won't have this questions further.
Set your limit, (lower and upper limit), then you won't have this questions further.