Fill a medium pot with water, add salt if desired, and place it over medium to medium-high heat until the water reaches a rolling boil.
While the water heats, inspect the green beans and trim the ends if they look wilted, woody, or especially fibrous.
Add the beans to the boiling water and cook for 6 to 8 minutes.
Remove one bean carefully, cool it under running water until it is safe to handle, then taste it. If it is not tender enough, cook the beans for 1 to 2 minutes longer. Keep in mind that they will soften slightly after draining.
Drain the beans well and return them to the warm pot.
While the beans are still hot, add butter and season with garlic powder, onion powder, salt, and pepper. Stir to coat, then serve. (See notes for an alternative version with bacon.)