If you leave them alone, they will probably leave you alone, although some wasps may be more aggressive in the fall when fewer food sources are available. Be aware that honey bees can only sting once, but wasps are able to sting repeatedly. Stag beetles are related to scarabs. However, they are a little more aggressive. The males have very large mouthparts called mandibles that can inflict a very painful pinch if they are mishandled.
Blister beetles can also be harmful, especially to livestock.
Their blood contains a substance called cantharadin which will cause blisters if it comes in contact with skin or is swallowed. What actually itches when mosquitoes bite is the saliva that is injected while the mosquito inserts her mouthparts under the skin. Mosquitoes are found most frequently near water, although they can travel a fair distance looking for hosts. Besides lakes and streams, mosquitoes breed in any pool of water, such as birdfeeders, puddles and old tires. UK Dept. of Entomology Most 'true bugs,' a group of insects including stinkbugs and boxelder bugs, are harmless.