Thanks for your question. The whole insurance business is based around the concept of evaluating the cost of risk and then charging above and beyond that cost to the consumer, thereby making a profit. However, this does not mean that travel insurance is a waste of money.
On my first trip to SE Asia I contracted a nasty stomach bug after swallowing river water and felt the most ill I was in my life; I also dropped my camcorder in the sea getting out of a boat (I slipped and fell and dunked my bag under, hehe). Both these unfortunate episodes were covered by my travel insurance, thankfully.
I guess you have to evaluate your risk yourself. If you are not bringing anything of value, then you may feel you have no risk in losing any possessions. But what you can't evaluate is the risk of falling ill in Thailand. Hospitals are cheap for minor ailments, sure, but bills could add up if you contract something more serious such as dengue fever or the like.
At the end of the day, some backpacker policies (basically health coverage plus insurance of possessions of low value, usually £100 and less) are so cheap these days that I wouldn't consider travelling without insurance to Thailand. But that's me.
I really wouldn't rely on tarot readings to predict how safe your trip will be! At the end of the day, your safety is going to be heavily based on how prepared you are (know the dangers and scams), how much common sense you have and how you behave (i.e. don't get whacked out on drugs and/or alcohol and wander back home on a dark beach alone or ride around uninsured on a scooter without a helmet). The rest is going to be based on luck (or rather, unluckiness).
I consider myself to be a genned-up, experienced traveller who is risk-averse and has plenty of common sense, but even I find myself the victim of cons or placed in potentially risky or dangerous situations now and again. Having insurance as a backup is peace of mind if you ask me.
Safe travels, whatever you decide.