How you feel is part of a thought process.  This process is centric to YOUR brain.   The brain is not autonomous for most things (exceptions are basic things like normal  breathing).  In fact, the behaviours and feelings derived from  the data you receive from your brain are yours to control and yours alone.

The brain does not action, it provides data which you use to decide and implement action.  Therefore, logically, you will never feel bad.  Why would anyone decide to feel bad.

The operative descriptor here is “bad”.  By definition the things described as bad are negative.  Negative is typically not a desired state of being.

People do feel bad

The simpliest explanation for choosing negative feelings and the associated depressed and sad behavior is based on the analysis of the data.

You parsed the data provided by your brain and decided the most appropriate internal response was to feel bad.

Personally I wonder what the value equation is.  The data could be a death of a close friend or relative, loss of something you hold dear and a thousand other things as simple as dark cold days.

My own approach is to feel good, regardless.  Why not?  In truth, up to the point of my own death, anything but feeling good, upbeat and happy seems pointless.

I choose how to feel, act and behave and logic dictates sad unhappy feelings make little sense.  Maybe I am part Vulcan.