Shoot Yourself in The Foot More Efficiently
If you’re unfamiliar with how frameworks function, trying to use a framework for a new project will bring trouble. With all the complexities frameworks bring, new bugs will come, too. Besides, small one-man projects typically don’t require a framework.
MVC Isn’t A Framework-exclusive Feature
See the bare-bones MVC and the framework without a framework pages. If the MVC pattern is all you need, you can easily avoid the overhead of a fullblown framework.
My Business Layer Is None Of Your Business
Frameworks provide (and enforce) too much abstraction. In actual systems the presentation and persistence layers are likely to be very thin, sometimes indistinguishable from the business logic. This isn’t necessarily bad. Add too much frameworks, and you might end up with an interpreted language that runs on top of another interpreted language. See a more detailed discussion in The Mythical Business Layer.