It was quite the opposite way for me. Almost all of my engineering courses were in metric. In fact, most of us considered it a 'trick' when english units were

It was quite the opposite way for me. Almost all of my engineering courses were in metric. In fact, most of us considered it a 'trick' when english units were used. Conversions for the metric system seemed much more intuitive for me in math. However english units seemed much more noticeable since they are mostly unique (didn't miss a 0 in a conversion). Lastly, I agree with a comment below that this is largely a problem of getting rusty. After living both in Europe and the US for significant portions of time, I still have trouble between Celsius and Fahrenheit.