Your question could potentially spark a whole host of responses running the usual gamut in the forum from sarcastic to glowing so it will be interesting to see what others have to say.
It is actually one of those things that is typical of the problem of "generalization" which is to say that one really can't draw very good conclusions based upon a limited experience (including their own) and state something so generally as that being a Jehovah's Witnesses gives you this or that trait.
People who were, are or will be Jehovah's Witnesses are just like people in any other group and have a mix of both "good" and "bad" character traits which are manifested to greater or lesser degrees in various persons and that is really all that can be concluded.
The second problem is that we have a "chicken or egg" problem of figuring out whether someone who says they have a "positive" or good character trait, may have had this trait regardless of being a JW or not. For example, you cite your guy's patience and reasoning ability and willingness to go to you and talk to you about issues/problems. But can one say whether he would be the same way had he not been a JW or can we say positively that being a JW TAUGHT him to be this way.
What this is really is the age-old debate about personality and character and whether such aspects of such are the product of natural/genetic features, social-familial influences or learned from some more external source such as a religion.
Anway, you did ask, as best as it can be asked, for us to name some positive character traits that WE developed personally, so I will try to name for you just a few things that I do think that I did learn being born and raised in a JW household (and being an active member in adult life): (this list I could probably make very long but I will just name a few for you)
1. I do think that I am somewhat less materialistic than I might be not having been a JW. Probably, more accurately is that I don't tend to place a whole lot of value on tangible, material goods or trying to strive after these in my life. I don't subscribe to "the man with the most toys wins" philosophy.
2. I believe that when it comes to "injustice", "revenge", "getting-even" or witnessing or receiving mal-treatment and all of these similar things, that having been reared as a Witness permits one to take a very casual and even healthy-minded view that such "evil" ones are best left in the hands of God. This is not to say that I don't intervene when I witness such things or defend myself if they occur to me others near me, because I certainly do.
3. This one is hard to convey to the non-Witness, but I will try. There is a certain PEACE of mind and general comfort in all aspects of life that results when one understands a lot of the REALITY that is the truth contained in God's Word. (Unfortunately, often this trait can slide into and present itself as a smugness or arrogance in many a Witness.)
It is these fundamental kernels of truth that I believe are so attractive to a person who becomes or remains one of Jehovah's Witnesses. Unfortunately, it seems to be that only a few Witnesses fully appreciate these for what they are because what occurs is that these truths get covered more and more with all of the moronic and scripturally unsound doctrines and organizational cultural artifacts as they get deeper and deeper into being a JW.
For many ex-JWs and JWs who have managed to shed these outer layers of falsehood and unscriptural teachings and cultural practices, what often occurs is that these fundamental truths had become so fused with what was stripped that they themselves are not even present anymore and so these attractive truths are lost.
However, if an ex-Witness, or current Witness, can come to terms with reality--and that reality includes both the truths and the lies of the Watchtower, then what can result is a very centered person, one who is often more mentally and emotionally healthy than many a non-witness or other Christian.
4. Finally, and this is obviously very subjective, but I believe that I have many trivial traits such as not-cursing, fairly good manners, cleanliness, orderliness, a certain amount of studiousness, argumentativeness (which I consider a positive trait), outspokenness, public speaking ability, moderate in drinking, never smoked anything, never did an illicit drug of any kind, not a big gambler at all (except the occasional lottery ticket), tenderness, appreciation for the natural world (creation), Golden Rule-applicability, respect for elders, yada yada yada -- all of which significantly if not largely resulted from being one of Jehovah's Witnesses.
On the whole, JWs in a large part are very good people. If you were broken down on a lonely country road and had two houses to choose from: one a non-religous household and the other a Jehovah's Witness household, you would be safer, more welcome and taken care of at the JW house. Trust me on that one.
Too bad they wouldn't let me in since I am Disfelloshipped :-)
ps: you might have more FUN and/or Adventure at the other house...cue the jazz music: wow-wooo, woo-WOOOOW :-)