If you ask the question "what are mosquitoes good for" most of them will answer you : nothing; they only irritate us and gives us a lot of trouble. Surely in Summer and we are sitting on a terrace with a glass of beer or a glass of fruit juice the mosquitoes are there and gives us a lot of trouble like biting and it gives us some itch. The reason that mosquitoes bite is that they are searching for suck blood. They need the proteins in this blood to make their babies.
But these people are wrong by saying that it was better that mosquitoes shouldn't better don't exist. Like every other insect also mosquitoes are useful to maintain the nature. When mosquitoes are born and called "larvae" they eat little insects which are in the water and that is useful when there are too much of them. They keep the water clean.
Adult mosquitoes can't eat anymore but they are food for other animals like a spin, some birds and fishes.
I don't like mosquitoes because they give me a lot of trouble but don't forget they are useful for the nature.