Let's say you want to introduce someone to RPGs...
This seems to keep cycling around to the person you are trying to engage. Maybe we can help better if we know a little about them?
For myself, my first systems were D&D 2E, Earthdawn, and Palladium Rifts. Those can be a degree of daunting, but I had a lot of good help jumping in.
By contrast, a friend of mine has panic attacks and melts down in anything more complicated than WoD even though she's been playing and GMing for years.
When I run games for people new to RPGs (which I have more than established players at this point) I do something similar, but not exactly like what DarkLightHitomi suggests.
I ease players into systems. For me, that looks more like sitting with someone during character creation and going over their character sheet in layman's terms. I really feel that it's important that they build and understand to some degree what's on their sheet since the mechanics will have to be learned at some point anyway, but it's easiest and most relevant to start with what will matter the most to them to start, which is their own character. At the same time, I feel it's completely fine to point something out and say, "we aren't going to worry about this yet, but this is what it is just so you've heard about it." Or, "This is supposed to be fun, so if you decide you don't like something now, we can always go back and fix it later." Similarly, just because something is on a character sheet, doesn't mean they have to use it either at first. I'd point to Pathfinder for some of this stuff. Put it on the sheet and go back to it once they're used to the simple stuff.
Then we can move into simple scenes for them setting up the rest of whatever you want to run for them. Maybe an urchin just stole their wallet, or someone else's and they need to run after them, dodge a few things, ask about where they went, and then draw a weapon on them when they are found. It's a simple thing to run and you get to show them how to use their abilities (how to walk, so to speak). Typically, I'll run a handful of sessions with basic mechanical things like that to build a solid understanding of the base mechanics before moving into things like special attacks, called-shots, etc. That doesn't mean the game has to be boring, just that the first events they face aren't going to require chained attacks or complex magic rituals, or anything like that to succeed. Similarly, I don't use more complex rules for NPCs or adversaries until the player is comfortable using those as well. Sometimes players will jump ahead of my tutorial also, and that's fine, too. ^_^