TITLE: Looking for a significant example that highlights the suboptimality of the greedy algorithms
QUESTION [5 upvotes]: A week from now, I'll have to present my work to a bunch of coworkers who aren't used to the optimisation world and terminology. One of the main algorithms I implemented uses a greedy type algorithm (a multi-start randomized greedy algorithm), and I'd really want to make two things very clear with simple examples : what the greedy algorithm is, and why it is suboptimal. 
I thought of giving examples with the shortest path problem, but I'm looking for real life examples, maybe situations where we naturally use a greedy approach unconsciously. 
Can you think of anything ?

REPLY [3 votes]: Putting coins into a vending machine, or making change. The objective is to minimise the number of coins used. A greedy algorithm uses the highest possible denomination coins first. Whether or not the greedy algorithm is optimal depends on the coin system. In both US system and the Euro system, the greedy algorithm actually is optimal. More info here.