I think I’ve been to the Louvre 3 or 4 times in my life, once or twice before they built the pyramid entrance and once or twice after they built it. The first time I saw that pyramid, I found it to be very incongruous (to say the least!) to the general building style there. But it’s grown on me, and the entrance facility underneath is terrific and very necessary. One time on a business trip to Milano, a colleague and I had the weekend free, and he’d never been to Paris. So we took the Thursday night sleeper train* to Paris, spend Friday, Saturday, and most of Sunday in Paris. We went to the Louvre and literally, at a super-fast pace, went through the whole place in a little under 3 hours. I wonder if that might be a record, LOL. I don’t recommend doing the Louvre so quickly, it’s much more enjoyable at a leisurely pace, even over 2 or 3 days if you are a true art lover. But we were trying to hit all the major Paris stuff in one weekend. We skipped the Eiffel Tower, even though our hotel was only a short walk away, because it felt like a tourist trap to us.
* The sleeper train was an experience in itself, we had 6 people in our compartment. Unfortunately one of them had severe body odor, so my colleague surreptitiously sprayed his deodorant roughly in his direction periodically. We made it through the night with some sleep and arrived at Gare de Lyon (IIRC) in the morning.