What are your opinions on gap years?

I have sooo many questions. This is just an outpour of all of them. I definitively want to attend a college/university, I just don't know if this speedy transition from highschool to college is right for me. I'm also unsure of what I want to study; I have a slight inkling of the path I want to follow but not the major. Is it smart to apply to colleges/universities and additionally apply to a gap year all at the same time, and then later make the decision of what I want to do? Can gap year programs actually accept and reject applicants or is the decision final when I submit my application to the gap year program? Could you curate your own gap year without a solid program, and could the gap year still look interesting to colleges? If I did decide to take a gap year and I was accepted into multiple of my top colleges at the same time, should I make the decision what college I want to attend immediately and then defer my attendance by a year, or should I reject all of the college acceptances because I possibly don't know where to go, and then reapply during my gap year? Would colleges that I reapply to possibly frown upon my decision to reject their acceptance, take a gap year, and then reapply?