The most important thing about work is the necessity to get it done. Smoke enough weed and your coworkers will lose so much track of time and focus and be too relaxed to do just about anything. Instead of working, they'll be staring at their fingers, singing Judy Garland and eating McGriddles at 2 PM.
Say what you will about crackheads, but they get the job done. It's a powerful stimulant that will keep them alert and going throughout the day better than any Red Bull could. Sure you'll have to put up with constant sniffing and trips to the bathroom every half hour, but it'll be worth it come quarterly reports time.