Many insects, such as grasshoppers have small claws that they use to hold on, but these do not work well on glass or on ceilings. Insects, spiders, crabs, and scorpions are all arthropods. This means they all have an exoskeleton and jointed appendages. Insects are different from other arthropods because they have six legs and three body regions. Spiders for example have eight legs and only two body regions.
Bees do a lot of good by pollinating flowers.
The beekeepers then sell the honey that the bees make to grocery stores. Wasps also do a lot of good. Wasps either eat or parasitize other insects and spiders. This can be very helpful in reducing the number of pest insects in an area.