All I usually say is that it is for personal satisfaction. Can't deal with it, then bugger off. I think it's kinda sad that people immediately assume those very involved online usually don't have a life elsewhere. It's all in the mindset. Stereotypical views of the world.
Web design is a talent a lot of people have.
Others pay to get into sports teams and to buy art supplies, among other things. Now THAT is definite good web action for those in doubt. I am a sad web addict with no life. But if you're lazy, the word caper just means a small crime. So i was trying to pun with ca.per.