Bond conundrum?

Why is it that when markets deem an economy as healthier, the yields on its bonds go up and naturally bond prices fall? I understand the movement of people out of safe assets into higher yielding investments but it has always seemed strange that at a point of maximum safety you are both 1. paid more in yield and 2. able to purchase the bonds for a more affordable price. Seems like a good way to "buy when others are greedy." Look forward to discussing.