When I was a child (probably 5-6), I remember my parents buying a few bettas for us (my brother and I). Unfortunately, my parents did not research proper betta fish care, and the poor things lived in probably 1/2 gallon bowls/vases for their entire lives. I remember always thinking that the cups and tiny bowls must be cruel, despite what I had been told by my parents and pet store employees. We also always seemed to have at least one tropical community tank- which was equally uncared for- but I eventually gave mine to a family friend because the filter was too loud for me to sleep (at this time I was probably 13).
A few months later, my room just seemed very empty and lonely without any fish, so I decided to get a betta. However, I was then old enough to disregard what I had previously been told about betta fish (and just fish in general) care, and did my own research on the subject. Of course, once I learned about proper fish care, I was horrified by what I had believed as a child and the subpar care my previous pets had received. So, my new betta was housed in a heated, filtered, 5.5 gallon tank.
It did take a little while for me to amass the necessary knowledge to keep truly healthy and stable tanks, but I then moved on to rescue quite a few fish over the next few years. The last of my bettas died of natural causes a year and a half ago, and I am now waiting to get back into the aquarium hobby until I have a bit more time on my hands (I am a prevet student right now, hoping to attain a doctorate degree in veterinary medicine and become a surgeon). During breaks, however, I am working on conducting research about various fish ailments because I have found that research in this field is sorely lacking (unfortunately, it just doesn't pay). So, I figure that I should take advantage of the time I have now (I probably won't have much spare time in my future) and make a worthwhile contribution to the aquarium hobby :)