Hobby is occupation, which is done not for money, but for pleasure. Different people get pleasure from doing different things, as very person has his/her own likes and dislikes.
People choose their hobbies according to their likes and dislikes, tastes, style, their financial state and education.
Hobby can be divided into four groups : doing things, collecting things, making things and learning things.
It also can be dangerous, for example, if you collect some wild animals, such as snakes or spiders.The most popular hobby groups is collecting things, because almost everyone collect something at some period in his life stamps, coins, matchboxes, records, post cards, toys etc. But sometimes in can be very expensive. For example, if you collect some rare and valuable coins or some original paintings (pictures).
Another kind of hobby is doing things. It includes a wide variety of activities; such as going to the cinema or theatre, playing computer games, doing sports, traveling and gardening, which is very popular in England.
The 3 rd kind of hobby is making things. It includes drawing, painting, making sculpture, designing costumes, handicrafts and others.
One more kind of hobby is learning smth. People learn foreign languages, read books on different special subjects, go into various expedition.
As for me, I like kniting by nook. This is hobby makes me more quiet.