In the 21 year run of this show, I really can't remember ever seeing a Mother's Day episode. It was actually pretty good. Definitely don't see a lot of episode revolve around the trio of Homer, Apu, and Reverend Lovejoy. Moe's voiceovers made this episode good, but it was ultimately nothing special.
I did love the ending montage of the characters and their mothers. It was particularly touching to see the photo of Homer and Mona, long after she was killed off.
This is the first time in a long time where I felt like we had quality back to back episodes. I loved last week's, which didn't even get a thread here, and thought this one was close. This show has been on over 20 years and has seemed to have somehow claimed funniest show on Sunday Night again. It's good to see, and it always helps when they go deeper in the character pool.
I think you are wrong about Jennifer Aniston. Watch Friends With Money or The Good Girl sometime. I think she even did a fine job in Picture Perfect for what it was. This was a great movie, and its worth seeing for the supporting cast alone.