Manners are free

If you are at a disco and you get asked to dance, the polite thing to do is say yes. If you own a stair-building company, and someone asks you to build stairs, you should also say yes. However, don't dance on the stairs until the concrete or glue has set, unless you are both very light on your feet. Sometimes you have to be impolite to save lives. Ask to see dance certificates beforehand, you can't always trust people who just want to dance on your new stairs.