In my very humble opinion:

1. If you're money minded, you will not find it easy to be a good doctor and make a lot of money at the same time. Although being a good doctor does not preclude the practitioner from becoming wealthy, the trajectory of wealth accumulation and generation will be vastly different to that of a successful businessman. It's not uncommon for passionate doctors to take a long time to accumulate wealth, as opposed to people in other professions. A lot of times, doctors make decisions against their own interests - because the patient's condition and illness demands such a conclusion. A simple example is do we give oral antibiotics for what is likely a simple viral infection of the throat with fever? If we don't, we lose out on the margin of profit from the sale of antibiotics, but if we do, we expose the patient to potential future antibiotic resistance because the antibiotics were given unnecessarily.

2. Doctors don't make good investors - because investors sometimes have to take risks to realise big gains, and doctors need to be risk adverse, as taking risks may end up harming the patient's outcome when a more conservative option would have been the safer decision. An example would be conservative treatment vs. surgical intervention for cervical spondylosis with radiculopathic pain. Conservative treatment involves analgesics, nerve relaxants, physiotherapy and the use of a soft neck collar. It's slow, boring and unexciting - but it's safe and most patients do eventually recover. Surgical intervention may involve laminectomy and disc/spine fusion and reconstruction and "cement" injections. With any surgery, there are risks involved - and the ultimate risk is the patient may end up being paralysed and a quadriplegic or a paraplegic. And, if you find yourself armpit-deep in the red from your forays into the stock market, would you then be tempted to push the envelop of risk for your patients, in order to recoup the paper losses?

3. In an ideal medical scenario, money and medicine are mutually exclusive - medical care is given solely only to those who need it, not to those who can best afford to pay a premium for it.

The attitude, character and personality required to be a successful - and dedicated - doctor is quite different from many other professions. I'm not the final judge or arbiter to say one is better to the other; in fact, it's merely different. You'll have to find the profession &/or specialty that best suits your personality and character - otherwise, you may find it a miserable existence for the next 40 or so years of your working life.
bauer, truer words were never spoken. Well done & welcome back to Malaysia.