Time to fly
When I was waiting for the bus to go home for lunch (I'm 10 minutes away from work and I have a bus pass) I noticed another bumblebee working the butterfly bush thicket by the bus stop. It was close to the chainlink fence that separates the sidewalk from the lot that contains the thicket, so I couldn't resist the temptation to take a few pictures. With the flash turned on.
Well, it turns out that this bumblebee was a sensitive sort. As I was clicking away, it turned and glared right at me, then jumped into flight and started flying around in a moderately indignant fashion. I took the hint and retired from the field, and only realized that I'd gotten one takeoff picture when I reviewed the photos when I got home.