Practically the first thing I learned to cook was pasta. And also rice. They are both very easy. You put them in boiling salted water and cook for the length of time it says on the packet. For pasta that is usually shorter than for rice. (3-15 minutes rather than 20-40 minutes.) Once that time has passed you strain it through a sieve or colander and eat it. You can tell when it is ready by picking the odd bit of rice and pasta out of the boiling water with a fork and testing it.
I am not a fan of boil-in-the-bag rice. It is messy and inconvenient to serve; you inevitably risk scalding yourself as you snip the bag open. Much better to cook the rice swimming round freely, and chase the last few grains out of the pan with hot water from the kettle. (Also you can use that water to rinse the rice as it sits in the sieve, a technique my future wife taught me.)
An early variation on this basic boiling technique which I tried in my late teens was to tip a packet of soup into the rice or pasta as it boiled. Also eating it with a lump of butter can mildly diminish the sense of despair which is easily generated by such a diet.
There are other foodstuffs which respond well to the basic boiling technique - essentially, almost all green vegetables and many of other colours as well, which can be bought in appropriately cut ready-to-boil servings, both frozen and fresh. Some of these do take a significant preparation time. For instance, I like eating potatoes, but I resent the time it takes to clean them and scrape them, and if pasta or rice is available for cooking instead I will almost always choose them. On the other hand I love cooking peas; chuck 'em into the water (with some mint if feeling adventurous) and three minutes later they are ready to eat - the perfect afterthought vegetable.
The other food which I enjoyed boiling even in my early teens and still love today is the humble egg. Soft-boiled inside the shell, they furnish a self-contained hot meal (best at just about five minutes, so that the yolk is still runny but the white more or less set). But even better, crack them into a pan of hot salted water, extract with a slotted spoon after three minutes and deposit onto your thickly buttered toast, and you have the poached egg breakfast which sustains me most mornings.
My culinary technique has moved on from simple boiling - or at least I like to think so - but this is where it started.