For me, I noticed that herbs like basils, mint, corianders, etc.. are much more perky in the morning. I pick them in the morning.
As for Mangos, most definitely, best time is to beat the rats and squirrels. They tend to know when fruits are ready to eat. I just thought if anyone ever experiments with the time of day as to when to pick mangos that would give the best flavors? Since I don't have many mangos to do the experiment, maybe you folks with huge mango tree can test it and compare notes? I might be able to experiment with it in the next few years. Right now, not lots of mango to play with. Plus, my family tend to like eating green mangos for salad.