If I start a sentence when I'm talking to you with "the thing is..." in English, you already know. You already know that I'm about to give you an excuse for why I can't, or it couldn't, or I won't, or you shouldn't. It's probably even not necessarily 100% true. The thing is... I'd like to but... or the thing is, I know I said I would go but...
Valuable little expressions like this, in addition to well, you know, etc, are called muletillas in Chilean Spanish. It means little crutches, and they're the words and expression you pepper your speech with to soften the content, or move things along. So... as I was saying, you know, stuff like that.
Chilean Spanish is replete with muletillas, and of course has it's own version of "the thing is." In the words of my good friend T, "Lo que pasa es que" (literally, what's happening is) is the introduction to an excuse for why you haven't done something you should have. "Lo que pasa es que no he podido (The thing is, I haven't been able to...). She says that any time she hears "lo que pasa es que," she immediately turns of her active listening because she knows that whatever comes next is for sure a rationalization of why not. And she doesn't like that. People should just do what they promise to.
So what I'm trying to say is that the thing is, I've been meaning to write all day about how amazing these experiences here in the south have been but lo que pasa es que I'm having too much fun to sit down and write about it.
In more famous sayings and expressions news: so sue me.
Wed back to Santiago and the regular schedule.