Learn to guesstimate big numbers. It will help reduce your apparent anxiety when confronted with American imperial units of measurement.
It takes about a second or so of guesswork - 1000 feet is about 300 meters. 2000 is 600. 75% of 300 is 225, so we get a guesstimate of 225 + 300 + 300 = 825m . In reality, we're off by about 13, but remember, that doesn't matter. If you're really good at math, you could subsitute 304 for 300 and get closer to the reality, but why bother? The more you do conversions like that, the easier they get.
Out of politeness to your future self, you should adjust your attitude and simply accept that sometimes you'll have to think a little bit. Not much, fortunately, but a little.
And if you absolutely can't handle it, then take responsibility for your own information consumption and install an automatic converter. There are plugins for firefox and chrome that automatically convert units to and from metric and imperial. You can even auto-convert units of currency. You'll never have to waste another second on translating again.
Real politeness never imposes on others. Do unto others as you would have done unto you has a nice corollary: do for yourself what you'd expect to do for others. At some point you have to take care of yourself. :)