Solid Snake is a lifelong soldier, who spent a short period of time with surrogate families before joining the military at a young age. Now in his thirties, and after numerous solo missions, Snake prefers to be alone, reserving his emotions and often described as uncaring. Although he does believe strongly that some people need to die, and has been willing in the past to carry out those actions, Snake has also shown concern for allies who accompany him into dangerous situations, and has shown compassion to fallen enemies. His extensive military background has led him to believe that the battlefield was the only place where he truly felt alive, and has been accused of in the past of enjoying killing his enemies. Even though he tends to agree with this, conceding that he is "heartless," he has always fought to build a better future by destroying Metal Gears and saving humanity from the sins of his father's past.
Despite the horrors of war, and betrayal by his father, Big Boss, Snake has expressed his love for life, seeking out a life of his own while rejecting his father's title. He disagreed with the idea of being a hero, and often rebuked the praise of allies when lauded for his reputation as a legendary soldier. He believes that friendship and love can flourish on the battlefield, and that violence is not glorious, nor is there peace or happiness in death. There is no love loss between the military or the United States and himself, but he has always strived to be self-sacrificing. Previous to the plot of Metal Gear Solid, Snake suffered (and continues to suffer) from PTSD and emotional trauma caused by having to kill his father, and retired to Alaska to throw his life away as a musher, suffering alone from alcoholism. However, during the end of the game, he comes to terms with his life as a clone, and Snake ends up taking Naomi's advice to not be chained to his fate, accepting who he was, while resolving to live.
Still, even though Snake made a promise to himself to live the rest of his life to the fullest, he is a loner by nature, settling instead for a life alone rather than burdening others with a relationship with him. He has, however, still shown an interest in women during his missions, expressing interest in intimate relationships, and has flirted with his female teammates on several occasions. Most of that can be considered posturing, however; after the events of Metal Gear 2: Solid Snake, Snake promised Holly White, an American freelance journalist and undercover CIA agent, to meet for Christmas dinner, but instead chose to retreat to the Alaskan wilderness alone. In Metal Gear Solid, professing his love for Meryl, he would instead leave the FOXHOUND unit and her behind to create Philanthropy, an anti-Metal Gear NGO with his friend, Otacon.
As long as Snake is wearing his bandanna, any weapon he's holding will never run out of ammunition.
When Snake repeats the end of someone's last sentence back to them as a question, they are then compelled to exposition honestly.
When Snake hides under a cardboard box, you are compelled to stop looking for him, nor do you question why there is a random cardboard box just hanging around wherever you are.