You shouldn't hide your personality. Be proud of who you are and be true to yourself at work too. But, try to even out intense emotions a little. If you are really angry or stressed, try to use some calming techniques like breathing to regulate yourself. Don't project your negative emotions onto your teammates or it will ruin the atmosphere, cause tension and make it difficult to get work done.
The same is true for intense positive feelings though. If you are too excited and are talking a mile a minute, or are pacing, or off task because you're excited about something else it can also be difficult to get work done.
So do try and be calm, but still be yourself. It's ok to laugh and smile, just don't go overboard.