How is it causing trouble to say "excuse me, I had a latte with my order. Thanks!!"??? I'm polite about it and I wait ample time to make sure they truly forgot and aren't just behind. Hell, usually I'm actually approached by one of the employees when I'm just standing there waiting for a prolonged period of time, not the other way around.

But I only order 2 things. When I'm missing one of the only two items I paid for, I have a tendency to speak up. It doesn't make me an asshole. Believe it or not, there are polite ways you can indicate that you are missing half your order.

I actually don't correct them if they give me 2 incorrect items, so long as they are in the same category of what I wanted (a food and a drink item)...happens frequently. It's when I'm missing a category of item that I ask for it.