It could have been that very glass which was just dripping with a stomach virus, which was chuckling in its little virusy way and giggling its virusy giggle. I wasn't falling for it, though. That lasted until the first time I fell asleep, with two glasses on my headboard. When I woke up, I couldn't remember which glass was pure and which was tainted. The tainted one could have waited for me to drop off, then switched places with the pure one.
Tainted things are crafty like that.
And in a way, it didn't really matter, because I felt slightly better after sleeping than I had when I first went down to get the water, so the glass, formerly pure, was now a Minor Glass or Sickness. Or a Glass of Minor Sickness. Ready to re-infect me all over again. Another trip down the stairs was in order. I now have four Tainted Glasses in my room.