As babies become toddlers they know more of what they want and their stretch for independence is exerted. Often this time is trying on both the parent and the child.
A really big pet peeve of mine is when I hear a mom reply to her frustrated 1 year old in angst, "What is it, what do you want!?" Now, I've been guilty of doing the same thing when my toddler grabs at my leg and I'm doing the dishes and really just want to finish up those last 3 items so the kitchen looks semi clean for once. But, when I'm sitting enjoying play time with the kids, I've not had to feel this angst in trying to figure out what toy or object my baby is after or needs help with because I know more often than not they will be able to tell me, by using the sign for the item. And sometimes it turns out to be the darnedest thing, like a shoe that made its way into the playroom and is stuck behind the toy box.
When we have encountered these moments, far and few between, of not understanding our 1 year old's attempt at communicating, we've been able to use it as a teaching moment, demonstrating the sign so next time my dear daughter wanted the spinning top out of the drawer I wouldn't be at a loss. And more often than not, my 1 year old has been able to find a way to work their way through telling me what they want even without the actual sign because of their foundation in sign language.
I guess why it is a pet peeve of mine to hear the angst from a mom in this situation is that I have the tools to help them and they just haven't utilized my resources.