1. Tooth decay doesn't always look like a hole
A decayed spot on a tooth looks like a hole once it's pretty advanced, but early on decay, (caries), just looks like a white patch on the enamel. This is when the mineral has started to dissolve out of the tooth, but it's yet to break down and form a cavity. Interestingly, when early decay is reversed it can look even worse than when it's actively progressing. "Arrested caries" as it's known, goes a very dark, almost black colour. And caries on the root surface of a tooth where there is no enamel looks different again. Commonly there's nothing to see at all with your mere eyeballs if decay has started between the back teeth, which is why regular x-rays are so important to detect caries early.
2. Early tooth decay can be healed
If it's still at the "white spot" stage, the weakened enamel can be remineralised to reverse the early damage. This can be achieved through the combined effort of reducing sugar and acid intake, improving plaque removal, and using remineralising agents such as fluoride and/or CPP-ACP. This is well before any pain or sensitivity will be felt, so it's important to have regular examinations by your dentist so decay can be identified early enough that you can avoid needing a filling.
3. A dental x-ray is equivalent to 1/2 a day of background radiation
Just living on Earth exposes us to radiation, and while less is always better, radiation exposure is a part of life. The small dental x-rays that fit inside your mouth are extremely low dose, it takes two of them to equal the normal background radiation a human on Earth experiences in one day. Or 1/4 of the extra dose received from being on a flight from Perth to Auckland. Or the same as eating 50 bananas if you're so inclined.
4. Plaque changes over time
Left undisturbed, the plaque on your teeth, (which is made of bacteria and their by-products), gets nastier over time. If you remove or at least disturb the plaque twice a day, the really bad bacteria never get a chance to get established. This is the key thing about flossing: even if it seems like "nothing is coming out" you're still upsetting the ecosystem and preventing the plaque from becoming established. Immature plaque contains fewer of the disease-causing bacteria than mature plaque. You can even get dyes which are painted on your teeth to stain the old plaque vs the new plaque in different colours.
5. Pulling out a tooth has very little to do with pulling
When a tooth has to be extracted, it's mostly pushing and leverage that the dentist uses rather than a "pulling" action. The aim is to separate the tooth from the surrounding bone by expanding the bony socket, then the tooth can be levered out and left under your pillow for the tooth fairy. There's a common fallacy that dentists will use a foot or knee on the patient's chest to brace the pulling action, but it's completely unfounded and would not actually be a useful thing to do.