I got my first pet at 18, a dwarf hamster named chowder. After realizing how awful a pet he was, I kept him is whole life he was just left pretty much alone, I picked up 2 rats. I moved out the following year and was up to 9 rats. I've stayed fairly consistant at that number for the last year, I rehomed 2 boys and ended up buying 2 girls from work. I've bred another pair, but this time I made sure to have a couple extra homes lined up so that I wouldn't end up with everyone backing out last minute.
For a long time my mother would tell me, you need to spend money on yourself stop spending it on your pets. If spending my money on a new dog toy or rat treat makes me happy then who cares if I don't spend it on a new pair of shoes? Well its not how most people would spend their money so its weird.
I get a lot of crap for the number of rats I have. Luckily I work at a pet store so having a bunch of animals isn't really unheard of. Outside of work though most people don't understand 'collecting' animals. They just hear I have X number of dogs/cats/rats/snakes and its like holy cow how do you have the time for all that?! With less common pets its even worse, owning a single snake is strange for most people, owning a rack full of snakes, that's darn near crazy.
While most of us don't think having a large collection of reptiles or rats etc is strange, if some one told you about their extensive collection of noisy clocks you'd wonder how they every slept. If you aren't passionate about the same thing as someone else then of course it seems obsessive.