I would like to discuss this. I would say the difference is they're not walking/abiding with the source, we have a mission to accomplish and through the Holy Spirit God will guide us and tell us things. Wordly nice people only know a part of what goodness is but Godly/Christian people know what complete love is.
one is to love in truth:
1Pe_1:22 Seeing ye have purified your souls in
obeying the truth through the Spirit unto unfeigned love of the brethren, see that ye love one another with a pure heart fervently:
1Jn_3:18 My little children, let us not love in word, neither in tongue;
but in deed and in truth.
2Jn_1:1 The elder unto the elect lady and her children,
whom I love in the truth; and not I only, but also all they that have known the truth;
3Jn_1:1 The elder unto the wellbeloved Gaius,
whom I love in the truth.
note that you don't have to be someone's friend to love them in truth. i over heard the usual conversation the other day, "how do i love this person i hate".
simple love the brethren in truth, mind you truth of God. one should take into consideration how the Lord God loves and hates. God reveals the truth of himself is how He loves, and with holding the truth of Himself is how he hates. Jesus showed His risen self to the faithful (those He loved) not to the world. and if its a none Christian then some go by look to the sinner not the sin, which is really saying the sinner could be a future brethren. also the bible preaches to visit the fatherless and the widow. in spiritual terms that's those who do not have God as their Father, and those who are bound, or married to this world which in God's eyes is dead already, hence they are widowed spiritually.
but a pleasant disposition means nothing other than being available to others or not. and what one is available to others for is the question. a pedophile is pleasant and kind and presents himself as trust worthy because he wants something. a call center operator is pleasant also to get something or even if its to keep the job. so a kind demeanor proves nothing, and it certainly doesn't prove Christianity, or Godliness. those concepts are derived by those who want to define what a Christian is or should be in their own judgement. hence trying to create Christianity in their own image, and likeness because the god they worship is really in their own image and likeness and try to tell you its your God in the bible. which goes on all the time.