I'm assuming that you display a cordial, smiling politeness in your comments and gestures. I'm assuming that you board early and that you know the rhythm of the pre-flight minutes, so you aren't asking for something unreasonable. I'm sure that you express your gratitude clearly whenever the job is done well. Speaking up with kind firmness isn't really hard for anyone and needs to be done.
I do the same. I praise good service vigorously. I urge others to do the same. Service erodes slowly. With the possible exception of the 1K room at IAD, where they apparently were born surly and dull, service performance is a learned habit.
Decades ago, in another life, I worked a few summers as a flight attendant. I know from experience that in the midst of the repeating drudgery, it's easy to become impersonal, under-motivated and end up wondering why all these people sitting around won't help me do my flight attendant duties. Intended excellence slips to doing what seems to keep everybody quiet. Intentions of doing the small things fades.
I noticed a couple of years ago that small bits and parts of the total service were habitually being forgotten by many FAs.
When I mention service items (there are more items than pre-flight drinks in F/C), I kind of think of it as a way of helping UA survive. It's part of being a good customer, especially when there is not much that separates the competition than the front-line service of CSRs and FAs.