This is such a huge thing to be aware of. Some of my friends/ coworkers do this regularly and it's so painfully awkward to witness. Not only does it make you reek of desperation, but it forces the other person into a situation they never asked for and probably aren't comfortable with. There's nothing wrong with being bold and asking someone out, but for the love of god at least get to know the person first. All my best relationships started as friendships.