It's good to read on here how the posters who have submitted responses so far seem to stick rigidly to slot times.
Unfortunately the statistics indicate that "slot busting" is still a problem with between 10% and 30% of slots not being adhered to. This problem is not geographic or limited to busy aerodromes but is widespread.
There was up to 50% non adherence at LHBP (Budapest) who would appear to be the worst. More than 30% non adherence is not unusual though.
You are all aware of the effects for other controllers. The longer term effect of repeated overloads will be a general reduction in capacity.
Back to the thread though, there is no special treatment, no deals, no favours. This is looked upon very seriously here and is a disciplinary matter. Slots can normally be renegotiated or extended. There are a number of ways of accomodating missed slots and we will always try to help. The only time we will say no is if it is going to cause a problem for another controller further down the line.