Fun story: Once, when I was fooling around with a girl I only kinda knew, I asked if she wanted anything more to happen. It was one of those throwaway lines, and frankly I don't remember saying it. The only reason it sticks in my head at all is because a year later, when I mentioned how I only lucked into an awesome relationship because I decided to play along with her until she got bored. She reminded me of when I made the first move, asking if she wanted anything more out of the relationship.

The moral of the story? There's always a chance you'll misinterpret the other person. Including that you'll say yes to one thing when they meant something else entirely. Sometimes it works out well. Most of the time, not so well. All you can do is be thoughtful, and try to surround yourself with people who match that.