I wasn't raised to wash my hands after going to the toilet. (Toilet downstairs in a shed in the back garden, bathroom upstairs and only cold water, load of kids overpressed single mother etc).
As an adult, I read about the scientific basis for handwashing and thought eek. I am now an assiduous handwasher. I'm not particularly fussy about all kinds of hygiene, but I reckon if you wash your hands regularly then you're improving your odds of keeping well.
What surprises me about this thread is how many people seem to see nasty germ-catching as a zero sum game. Like you can see it or judge where it is (like the poster who wouldn't press the flush if she saw faecal matter on it) or that there is no point washing your hands if you're going to touch the door handle, like you either have germs or you haven't.
My understanding is that there's two points to this: one is avoiding obvious nasties (like poo on your hands), but more importantly it's about the herd immunity effect of having a whole population who wash their hands regularly, which would make an appreciable difference to communicable disease. Even if you just see visiting the toilet as an opportunity to remember to wash your hands, it's worth doing. It may be the first opportunity you've had since that bus ride this morning when somebody sneezed on you, after all.
Plus, I think I'm right in saying that antibac gels are not as good as handwashing. Useful as a top-up, but they can also irritate your skin and that makes it more vulnerable to germs and infection.