Guinea pigs are highly social creatures. They not only like interaction, but need it to be happy! This, along with the fact that they are awake for most of the day, make guinea pigs great pets for someone who wants lots of interaction with their small pet. Because guinea pigs need interaction with others, you must own two or more guinea pigs (and keep them together). If a guinea pig lives alone, especially without almost constant interaction with its owner, the guinea pig will likely grow depressed. 

Though guinea pigs love interaction, they will be timid at first, so you will need to gain their trust. Additionally, each guinea pig is different, and, for example, some may be friendlier than others, and others may be shyer.