I have a feeling this is a very american thing. Random encounters with the other sex were the norm in Germany (at least before tinder and the likes, no idea how it's nowadays). Being confident got you a long way. Not always, mind you. But often enough. Most women actually like being spoken to, as long as it's a friendly encounter. I believe it might be different in America because everyone there is trying to one up each other (often resulting in loud and annoying behavior). I wouldn't want to be chatted up by the cliche american guy either.