scarpa - no I had guessed/hoped what sort of cup you meant.
on a quiet road/motorway I can't see the harm in using one hand to take a swig of my drink - jeez - I hope you are not overtaking any of my loved ones on a motorway whilst you are taking that swig.
You cannot see the harm in it - I will pass on that as there is no way of explaining to you how dangerous this is, as you are clearly unable to grasp this.
Let's just concentrate on the fact that is illegal - someone I know was prosecuted for taking a swig of a drink whilst stationary at traffic lights.
Sadly people do not take safety seriously - they just want to do what they want to do, regardless of the possible consequences.
This sort of thinking is why I and many others fear driving - because we are surrounded by thoughtless drivers, who are unable to understand the importance of total concentration when driving and in so doing put us all at risk.
If you have never been to the scene of a collision at 30mph (closing speed of 60) then I assume that you are unable to grasp the potential for carnage when you have 2 cars driving at 70 mph.
One moment's lapse of concentration .... just one .... and you finish up with broken bodies, broken families. I know - I have worked with them and I cannot begin to tell you how many times I heard "if only" - if only I had not lost concentration; if only I had not been going so fast; if only I had not had that pint; if only I had had a proper rest before I set off; if only I had not reached for a drink at that moment..................
Take it from me, you do not forget these things - ever.
Cars are lethal - nothing less than total concentration will do, however much it might inconvenience you.