I worked in foodservice for several years with 1oz (30ml) and 2oz (60ml) portion cups, as well as a regular consumer of 12oz (355ml) aluminum beverage cans, so... I may be in the minority but I do have a pretty good frame of reference between the two.
Still I wish we'd gone through metrification like the government wanted to do in the 70's... There was even a renewed push in the early 90's too, under president Bush (41) but for some frustrating reason there was a lot of social resistance to change that still exists today.
They even went as far as converting one of our interstate highways to Metric as a test - I-19 between Tucson, AZ and the border crossing at Nogales, Mexico. Amusingly enough, although the Arizona department of transportation later added some signs in imperial units, the highway still has all of it's metric signage.