Without a a good bee suit, beekeeping, whether a profession or as a hobby, isn't much fun. You may not mean your bees any harm when you're interacting with them, but they don't always know that! Bees will likely attempt to defend their hive, and their stings can harm both themselves and you in the process. A bee suit is specially designed to offer three important benefits to keep both you and your winged charges safe and sound.
The main benefit of a bee suit is that it offers you protection from painful stings. Bee suits should fit loosely rather than snugly, which creates air pockets that prevent stingers from actually reaching your skin. While bee keeping suits made of heavy materials may offer additional protection from the stinger itself, lightweight cotton/poly blends are considerably more comfortable and still do the job quite nicely. The loose fit offers some respite from overheating as well. Bee suits should also have elastic at the wrists and ankles, which prevents bees from getting underneath the suit and gaining unimpeded access to your skin.
The light color of a bee keeping suit is yet another benefit because it keeps bees calm. Bees associate dark colors with predators such as bears or skunks. If you try to interact with a hive while wearing dark colors, you're likely to get the same treatment a dangerous and unwelcome invader would. By wearing a light colored bee keeping suit, however, bees are less likely to view you as an aggressor. In addition, should you get stung, you can easily see the stinger on the light colored fabric, allowing you to remove it and prevent the alarm pheromone that's released when a stinger detaches from calling other bees to the location.
Another benefit of wearing bee suits is they can help protect your bees. When bees do become alarmed, they go after dark colored areas. Bee suits with helmets made from dark mesh are good choices because bees will gravitate towards and sting this material. The mesh not only protects you, it protects the bees as well. Their stingers are less likely to get caught in the mesh, which means the bees may survive the sting. This good for the bees, but good for you too! When your bee suit prevents a bee from losing its stinger, it also prevents an angry pheromone-inspired swarm.