Approaching someone to ask them out on a date has to be one of the most nerve-wracking things in the world. Anxiety kicks in, you start to second guess every move you make and every single step you take towards them, your body is telling you to retreat, retreat, retreat.
You try to make things comfortable. You try to make it easier on yourself and less awkward when you strike up a conversation, but your heart is beating the entire time. Maybe you hit it off, maybe you don't - but whether you come off as a creep or not depends largely on the situation you're in. If you're in a club and you ask a girl if you can buy them a drink and try striking up a conversation, you're probably in the clear.
But if you're a pizza guy who took someone's online order, then took their phone number without their knowledge and texted them out of the blue, then, I'm sorry, you're being a total creepster.