The old adage about getting airborne because of the curvature of the earth definitely applied in Johannesburg.
Acceleration was painfully slow and one became very aware of the fence at the end of the runway as one trundled towards it. Then hauling the gear off the tar and then waiting (and hoping) for a respectable climb speed to clean up, even at relatively low weight certainly concentrated the mind.
And not helped when the slats retract during the roll, an outstanding job.
https://www.skybrary.aero/bookshelf/books/1319.pdf