One thing nobody's mentioned yet is dealing with really bad weather. Like Katrina weather. Or a tsunami. Fun stuff.
The one thing about tropical islands is that they tend to be in the tropics. The tropics tend to be home to a great many hurricanes each year. And every year, on tropical islands around the globe, some with very advanced populations, thousands of people die from these storms. The rest are left to re-build.
Living on an island, alone and with no technology you'll never know if those gathering clouds on the horizon (blocking out your beloved sunsets) are just a standard passing rain-shower,.. or a category 5 kill-storm.
Either way, you are powerless to escape either one. And if it really is a hurricane, then you can be assured a quick death, huddled in your wood and leaf lean-to you have constructed for yourself.
Native XWA.Netter (Nutter?)