It wasn't an experience. I'm speaking in terms of principle. Unless you live in plato's cave, tipping is an unspoken social rule, especially if you're going to a bar in the US. I've only bartended in major metropolitan cities, so my opinion maybe a bit bias.
I always, and always tip $2-3 for every $7-8 purchase. Do you tip the valet? Do you tip your cab driver? These are all rules that seem normal to me.
Has it ever occurred to you that the guy wasn't a good person to begin with? You're story telling puts him in a positive light, when in reality he just used you for your time and got information from it. If I truly appreciated you for what you did, I wouldn't be cheap and actually gift you something of worth.
I know I'll get downvoted but I'm speaking up for the bartenders that agree with me.