“Að slá einhverjum gullhamra” literally means to hit someone with a golden hammer. In Icelandic though, this means that you just gave someone a compliment. The saying can also mean that you’re hitting on someone—as in, you’re repeatedly hitting them with a golden hammer, i.e. you’re saying things like, “You’re perfect. You’re beautiful. You look like Linda Evangelista..” So hit away, but not with a real hammer. That’ll probably have the opposite effect. Unless they’re into BDSM or something. Get consent.