Obviously you're not going to complete entire projects in two hours, so you cut scope, while ensuring some version of "the thing you want to do" is possible.
So for insane forms with dozens of fields, you start with one field.
Then you iterate.
The idea is that at any given point outside of those two hours, your project can be used. It doesn't do ALL the things, but just enough to be useful.
What made it useful to you - the fact you could use the MVP yourself (internal motivation) or that you had an early user base breathing down your neck (external motivation)?
Did this approach work consistently, or were possibly other factors at play?
Obviously you're not going to complete entire projects in two hours, so you cut scope, while ensuring some version of "the thing you want to do" is possible.
So for insane forms with dozens of fields, you start with one field.
Then you iterate.
The idea is that at any given point outside of those two hours, your project can be used. It doesn't do ALL the things, but just enough to be useful.