Just Wondering

Tonight I was mowing and was chased by a wasp. He finally left me alone but he sure did scare me. I knew the nest was there and I guess I just got too close. Now, I 'm giggling thinking that I really should spray the nest but it is in David's boat trailer....need I say more?!!!
So, I continue mowing and I'm wondering what on earth are wasp good for? Do they eat bugs and help decrease the bug population? I guess I will be googling that one because I know that there just has to be some reason that they were put on this earth. Other than to zap us if we get too close!