I've also La Grande Jatte.  A couple of times.
The first time I saw it was in 1997.  I had just finished playing for Sunday in the Park With George at Arena Stage, and had just started working in northwestern Indiana.  On my first day off, I headed up to Chicago, and the AIC was my first - and only stop.  It was raining that day, and I still remember all the umbrellas on the steps of the AIC.
When I entered the French galleries, I first encountered the aformentioned Caillebotte Paris Street, Rainy Day.  But I was there for there for the Seurat, so...  After making my way through a couple of hallways, I finally found the room.  Wow!  The ceiling in that room is a skylight of sorts, but since it was raining that day, the natural light was kind of dim.  However, after a moment or two, the light suddenly got brighter - the sun was peeking through the clouds - and the painting really came to life.  WOW!
I just stood and sat there for at least a half hour taking it all in.  And, of course, I cried.
I've been back a few more times to the AIC, and I always make a point to visit the Seurat.  *And there's that one piece in the modern gallery that's composed of pieces of wrapped hard candy in a pile in a corner.  And, yes, you are supposed/invited to take a piece to consume.  Hmm... And then there's that other piece that comprised of a penny from each year of the artist's life all lined up in a row.  Hmm...  In any case...
It was also neat seeing one of the "cigar box" studies in one of the other galleries.  -There's also another cigar box study in the National Gallery of Art in DC.