Well, luckily, even at max take-off weight, we normally didn’t have any performance issues. Only once or twice had to say “unable” for short cuts to make minimum altitude on a departure.
Arrivals? Like Geneva, if a short cut was offered, even when replying “affirmative” on the radio, hand was already pulling the speed brake level to cater for the reduction in track miles / need to haul back the speed. Always mentioned it to new guys on the fleet during arrival briefing for there - this is the special Geneva lever!