Stop being a pussy, grow some balls /thread
You shouldn't care what others think to begin with. This is one of the spoils of the western 'civilization'. Everyone is obsessed about what others think. First it was women, now it's men too. Media to blame for sure. Including 'social media', so majority of society now is online. Interact with people every chance you get, not just online lol.
Lack of confidence comes from thinking of what others think about what you say/do/etc... That doesn't mean do stupid things or say stupid things and that's confidence. No... but don't think in every situation like it's an exam. Relax. You're not suppose to please everyone and don't expect the same back.
You could be smiling and a happy go getter guy, and you'll come across douchebags who will not say hello back, who will not smile back, who will be a dick. So what? Their loss not yours

Likewise you don't have to go into everyone's face like that either.
I guess it's something you learn as life goes on.