We are including way too much on most pages, one of the reasons is incorrect placements of include statements.

Solution:
1/ fix all activities to include stuff from locallib.php instead of lib.php
2/ go through all settings and minimise the includes
3/ go through all libs included from lib/setup.php and make sure they do nto include extra stuff
4/ make plugin lib.php files smaller by using locallib.php
5/ test, test, test - it is going to break big time because devs constantly forget the includes or put them to incorrect places