I agree that some things can rob you of the happiness of giving. The scripture isn't a law that's saying to give on every occasion because it will make you happy but rather a guiding principle. And I don't think it should be taken in isolation because, depending on the situation, there may other applicible principles that can affect your decision to give. "Don't throw your pearls before swine" may be applicible in the situation you describe. I don't know. You would know better than I. Sometimes situations are very complicated.
But in my experience those that can't be bothered to even give a "thank you" appear to be very unhappy people so you probably still gained more happiness than they did.
This is why scripture is useless as a moral or social guide. After all the cherry picking that eh! talks about, one has to then determine if any piece of advice is warranted in any given situation. In other words, one has to be aware of the situation, be aware of possible outcomes to the various behaviors, and weight the costs and benefits. This applies not only with regard to practicality, but preserving or strengthening social relationships as well as maintaining sense of moral code. As all this happens faster than you can blink your eye, scripture really has very little to do with determining social guidelines. Certainly not directly.
Instead, years of conditioning with regard to certain moral boundaries, including social ones, automatically drive behavior and we're left justifying, or regretting, what we've done. Scripture may be an indirect influence, but the social community is the primary influence. We can see this when we observe some xian groups embracing non-traditional qualities like feminism and LGBTQ persons, and others treating these issues as inherently dangerous. Yet both groups embrace scripture. In reality, both groups have developed and internally reinforce complex social expectations, then refer to particular passages to justify those beliefs, excusing others in some way.
I suspect when we talk about being happy, we're talking in some part about treating ourselves "right." I think we're applying the same mechanics to ourselves as we learn to apply to others. But, just like we have different rules for different people we know, we have different rules for ourselves. Ultimately though, the same process is applied by virtue of rewarding or punishing certain behaviors, and looking for cues of reward and punishment in order to modify our behavior. This video just encourages us to reward ourselves more and punish ourselves less. Sounds nice, like parts of scripture, but falls apart when looked at seriously.