In some places in the world (including Indonesia, Japan, Korea, Serbia, and Turkey among others) it’s considered a very rude thing to show, almost like calling somebody an unforgivable name! Yet, in Ancient Greece and Rome this gesture was a good luck charm created to scare away the evil eye, but also a protective fertility symbol. They saw that the thumb-in-fist looked a lot like the women’s genitalia and that the thumb sticking up in between the pointer and middle finger reminded them of a penis penetrating the female organ.
And lastly, the fig sign is the letter T in American Sign language!
So whichever meaning works for you, embrace it in your own way and beware of using it the wrong way at the wrong time!