Only nice to strangers

I spilled tea all over my chair today in class. Fortunately I was standing at the time, and class had just been dismissed (as much as college classes are ever dismissed - it's more like the professor stops talking and everyone decides to leave) so there wasn't a major ruckus caused. And fortunately our class is next to a tiny kitchenette (yes, I know that's redundant) so there were paper towels and a sponge right there to help me clean up the mess. The amazing thing is that no one mentioned my clumsiness in any way. Either we're finally grown up enough to not laugh at each other's shortcomings, or the other students don't feel they know me well enough to mock me, no matter the intent. Perhaps both are true. I suppose in that case, the question becomes: if they would laugh at me, should I assume them as friends?