It is the quickest way to connect with someone, well and people would really think you are weird going up to a stranger and hugging them giving out "Free Hugs." Myself, I find that when you walk past someone or look at someone just smiling makes me feel happy and when they smile back to you makes you feel even more happier. The one thing you will never find out though is they feel happy to or even cheered up as well. It really does sound a bit self centred but it is good that it cheers you up even if it doesn't cheer them up.
Although most likely by now you have worked out the bad things. What they could think of you, could possibly be really nice things or bad things. But the one thing they could think is that they could "Like" like you. Then again one you walk straight past you and most likely never see them again. Although can these things really beat a happy feeling?
So when you are out again try making yours and someone else's day and give them a smile.
