As an art student I'd get headaches and overwhelmed in museums. I mentioned this to a professor and he said, "Don't feel like you have to look at every single work in here."
With that simple reframing of the experience, I now can spend a lot more time in a museum, especially in front of the works I'm particularly drawn to. When we visited Paris, we spent hours at the Louvre every single day we were there.
Yup, the Louvre is just a monster. It really should not ever be done in more than 2 hour blocks, but of course you would need about 30 visits to get through the whole thing at that rate, which is fine for those of us that live in Paris, but not so good for tourists.
It's an amazing museum though, if you can avoid getting overwhelmed. I particularly enjoy doing the antiquities sections, with an eye for the technology used to produce the pieces on display. It gives you a new appreciation for the technical sophistication of the ancient Romans, Greeks and Egyptians.
With that simple reframing of the experience, I now can spend a lot more time in a museum, especially in front of the works I'm particularly drawn to. When we visited Paris, we spent hours at the Louvre every single day we were there.