What frustrates me about 1991 is so many of the best songs weren't lead off tracks.
I'm a firm believer in putting the best stuff first and the sound quality is already best on the outer grooves of a LP.
So many great songs are on the end of Side A or B and suffer from compression or inner groove distortion.
I don't know about the best song first but it has to be one of the best. A good writer uses thw first sentence to grab attention and set the mood. It's an introduction to the rest of the content and gets you fired up, or settled in, and excited for the rest.
I'm a big Alice in Chains fan and I feel like they were the masters of this:
And We Die Young (Facelift)
Them Bones (Dirt)
Grind ("Tripod")
Rotten Apple (Jar of Flies)
The Beatles were pretty good like this. Drive My Car, Taxman, Back In the USSR, Come Together.
Concrete Jungle (Catch a Fire) is one of the best mass introductions to a musical act that I can think of off hand. Maybe that doesn't count though since it was also the best song.