You might find your museum experience more enjoyable if you actually spend less time inside, and spread it out over a few visits. Photo by Robert Couse-Baker.
As Jeremy Anderberg at the Art of Manliness explains, "museum fatigue" is the phenomenon that occurs after you've been exploring a museum for a few hours. You start to gloss over exhibits, you stop reading plaques and you start to get bored -- even if you find the subjects fascinating. That's why Anderberg recommends you only spend a few hours a day in a museum, and try to make multiple visits, so you can really take it all in. Obviously it's not always possible (especially when you're travelling), but if it's a local museum, you can look into a season pass or just save some sections for your next visit. If you're travelling and will probably never come back, decided on your must-see exhibits and skip the rest. You can find more great museum tips at the link below.
12 Tips for Getting the Most Out of Your Trip to a Museum [The Art of Manliness]