Collecting fruit stickers: how serious can this be?

Looking over http://www.hobbieslist.com/ … this is not even a hobby…
I’ve seen many websites that try to give “hobby ideas”. I guess searching your hobby in a list works as well as having a list with people names to choose your friend from.
In my opinion there are 3 rules to call something a hobby:

1. You avoid naming the activity “hobby” to yourself. It’s some kind of little obsession or “passion”.
2. When some practical guy asks you “What is the use of doing that?!”, you won’t give an answer. It does not mean there is no serious reason. It simply means that your main reason is that you love doing it. By the way, that guy is narrow-minded ;)
3. You are actually going to learn interesting things from this activity but learning was never your main goal.

I’ll give an example. I collect fruit and veggie stickers. I must confess, I also collect the triangular labels from the cheese wedges since I was 10… Yes… these are two of my little obsessions.

What have I learned?
The number (PLU code) from the fruit stickers can actually reveal a very important thing
1. If it starts with 4 it is a normal veggie
2. If it starts with 8, it is genetically engineered
3. If it starts with 9 it is organic.
I am not the only software engineer under the sun… collecting fruit stickers and having this particular urge to collect small disposable things following of course two common sense rules:

The allure of like objects (that is, a set of things with similar size, shape, and whatnot) is difficult to resist. I am uneasy about the collector mentality, with its inevitable trajectory of ever-increasing sums spent on objects whose values are appreciated by a diminishingly small number of people. I can't stomach the idea of consumption as a creative pursuit. A more informal sort of acquisition - saving the disposable artifacts of everyday life - lets me satisfy the urge to collect. The rules for my fruit sticker collection are 1) each sticker must be unique (no repeats), and 2) the item of produce must be eaten by me.[Andrea Shiman- Fruit Stickers—The Overlooked Booty of the Lunchroom]

I tell you collecting fruit stickers is a serious thing… :)