In a production environment with real applications and important data people are not allowed to make tons of mistakes. Experiment and learn all you want, but I hope you eventually understand that what professional software developers and database admins do has very little relationship to weekend hackathons.
I know my clients won't tolerate "tons" of mistakes. Not even a few. In fact I am usually hired because the person they just let go made one too many mistakes with important data.
I used to work at a big professional shop. They made lots of mistakes, and the people who made the most fundamental ones were often promoted, not "let go".
The main difference in startups isn't that they don't build software the "professional way" and thus make avoidable mistakes. Instead, the difference is that startups recognize that the mistakes are inevitable, so may as well embrace them and build a process / culture around prototyping and continual refinement toward actual business value.
Pie-in-the-sky posturing about The One Right Way is nice, and especially nice when your BigCo is footing the bill, but when you operate under real constraints (e.g. economical) prototyping speed and simplicity can outweigh all the other factors.
All that said, I still think MongoDB full-text search was a bad idea -- only because their implementation is pretty naive and this corner is satisfied nicely in F/OSS by a number of other indexes like Solr, ElasticSearch, Sphinx, etc.
I know my clients won't tolerate "tons" of mistakes. Not even a few. In fact I am usually hired because the person they just let go made one too many mistakes with important data.