I think showing up to work 20-30 or even 60mins early each day or being the first person to work before the doors open each and every time and commenting on the reliablity of the bike and low maintance and health/fitness it has given you will definately be a positive approach to making people think abouthte times thier cars failed or transit failed (not often tho) or they got tiedup in traffic in grid lock.
A good way is to meet up with said people half way and ride with them the other half guiding and encouraging them. Take it up a notch and log thier progress daily/each time noting speed, distance, endurance so when they have a doubt you can show thier proven gains record to lift them backup again. Hey it works with people in the gym and you'll only get better.
It will really turn heads if you're a long distance commuter helping short distance commuters.
Zero_Enigma