connections

over the last 15 or so books i have read, i have begun to notice that each subsequent book has a connection to the previous book, and if i had been keeping track of all the connections, i would have a string of these elements -- an illness, a place, a type of character . . . .
for example, i just finished under the mountain and before that was leo the africanus. the connection? both had cross-dressers in them. awhile ago i read a book called the choice by nicholas sparks and then passed it on to my sister. i waited until she finished then asked her what she thought of the ending. only then did i realize that i was mixing up the ending of the choice with the book i had read, after ann, which i had just read before the choice. the reason? both were about a woman who was at death's door throughout much of the book.
i don't look for these connections. usually after i finish a book, the connection rises to the surface . . . this (place, element, situation, problem, thing) was in the last book i just read.