what pisses me off is the amount of pilots that I know have mode c or s fitted to their aircraft, that seem allergic to turning the knob to ALT.
Not only that but they are breaking the SERA rules of the air for which there are penalties if reported.
SERA.13010 Pressure-altitude-derived information
(a) When the aircraft carries serviceable Mode C equipment, the pilot shall continuously operate this mode unless otherwise dictated by ATC.