Comment by fragsworth

The process goes more like this:

1. Write some code

2. Test it

3. Debug your code

4. Test it

5. Debug your code

6. Test it

...

39. Debug your code

40. Test it; now it finally seems to work

If all your "test it" steps are being done manually, you're being very inefficient. A good unit test can actually make development go by faster with the added bonus of defending your code from changes down the road that might screw things up.