I joined British Telecom straight from school (some years ago I'll admit) to start an apprenticeship. One of the first things that I learned was how to position and use a ladder safely. It still drives me nuts when I see people doing it wrong.
It's downright dangerous - and what I hate even more is seeing people working off chairs or standing on dining tables to reach a bit of painting, wallpaper, whatever it be.
There's absolutely no need to take the risk. Think about how often you work at heights alone - and how long it would take anyone to find you if you slipped, fell and were badly hurt.
Aluminium ladders are really cheap these days. You can order them on Amazon and have them delivered to your door within 24 hours more often than not. Don't take risks when working at height.