Why? Because it holds you back.

If Hugh Hefner cared about what everyone else would think, do you think the entire Playboy empire would exist?

If Leonardo Da Vinci cared about what everyone else would think, do you think his Mona Lisa masterpiece would have been created? 

If Lady Gaga was too concerned with people thinking she was weird, do you think she would have become the music legend she is today?

No. So go out there and express yourself without holding back. You may go places.