I try when I can to avoid taking pictures during the big Masses, so most of these are either before or after the Mass. I did try to take a video of the entrance procession with the Pope at Pentecost. But I did not realize that my camera was out of space, so the video stopped just before he entered (a sign from God, perhaps?), and it took me a second to realize what was wrong.
The main reason I don't take pictures is because I think it is disrespectful to do so during Mass. The second reason is so that photos like this never happen (look in the upper-right corner of the photo):
That will teach me.