What are the biggest mistakes you've made so far in your startup journey? I'll go first...

Probably thinking too big and building the big vision first, instead of more focusing on testing of number hypothesis for best product-market-fit. So your frankenstein analogy actually applies to us somewhat. In our case, we became a community platform for so many use cases, that we ended up not being able to communicate it properly or execute upon the product. Now we're in the process of fixing that - the mission hasn't changed, but carving out individual use cases, KPIs, onboarding and communication became priority, along with assesing the depth of each market. It makes me think that startups that are founded on a big vision (I'd argue that is a necessary component to start anything), tend to run out of focus and resources to execute. Largely because they confuse search with execution, and ultimately end up with a sense of "impossibility" and feel lost. But it turns out that methodology is what needed to be fixed first - go lean, test methodically, measure stuff, follow KPI's, know you customer (KYC ;))) etc. This helps you move forward, keeps the team inspired, and also lets you avoid cliffs of delusion because "someone said they wanted something, so lets go and build that." Probably the shortest way to put it is that "Anecdotal evidence kills", or as they say in the military "Assumption is the mother of all fuckups".