Three unrelated examples of the importance of what you call things just hit me. One was mentioned by Tim Flannery in The Weather Makers. We humans evolved in tropical conditions, but we routinely experience and adapt to variations in air temperature of tens of degrees due to weather and seasonal changes. Given all this, "warming" doesn't sound like such a scary thing - warmth is good, right? And if the average change due to "global warming" is just a few degrees - we see bigger changes than that overnight! It just doesn't sound that threatening at a psychological level, and at the scientific level, it's awfully complicated. That's why James Lovelock (British chemist and originator of the "Gaia" hypothesis) prefers the term "global heating." I think "climate change" is also better than "global warming." In this case, what you call it is important, because it seems to affect how seriously people consider this important issue.
Another one is "space tourist" vs. "private space explorer" or other terms preferred by Anousheh Ansari and others who have paid their way to orbit (see today's Space Review for more on this one). I can see Ansari's point that her training was more akin to preparing for a Mount Everest climb (adventure travel?) than for a week on the beach, and I'm willing to use whatever name they like, though "space tourist" really works OK too. No biggy.
Finally there's poor, sad little Pluto, "demoted" to dwarf planet. Sorry Pluto, you're just gonna have to get used to the new designation. I just can't see the big deal over the Pluto thing - nothing has changed except a label that we use to discuss some objects in the Solar System. But we're still sending a spacecraft to visit in a few years, little buddy, so don't feel too bad.