What is the difference between treating someone as an end instead of as a means only?

1.
Treating someone as an end means treating people with respect; treating someone as a means is exploitive.

2.
Treating someone as means increases their happiness; treating someone as an end decreases their happiness.

3.
Treating someone as a means implies treating people with respect; treating someone as an end is exploitive.

4.
There is no difference between treating someone as an end instead of a means only.