I was one of those, 'why do you need a bigger phone' people. I sold my 4s.
Long story short, My mom wants me to sell her 4. Today I picked her 4 up off my desk to erase it and I was completely blown away by how tiny it seemed. I flashed back to all the things is thought about bigger phones & I finally got it.
For some it may take some time, but once you accept the 6 plus you wonder later how you ever managed without it. I'm in awe of my 6+ now.