If you ask someone out at work and they tell you, 'as friends only' that should be the end of your advances. If you continue past that point and say stuff like

If you ask someone out at work and they tell you, 'as friends only' that should be the end of your advances. If you continue past that point and say stuff like, "You're a Mom I'd Like to Fuck" that is clearly into sexual harassment territory. One polite and appropriate invitation to hang out (to a single coworker) is not sexual harassment. That is usually where the line is. Pushing after the rebuff is almost always trouble.