Well, no, I wouldn't add that because plenty who work full-time don't see part-timers as lazy or unmotivated (or may intend to do so themselves at some point if

Well, no, I wouldn't add that because plenty who work full-time don't see part-timers as lazy or unmotivated (or may intend to do so themselves at some point if they have a kid, for example). And sure...it may indeed be the case for some that promotions are slower to come by not working full-time. Hardly strange- if you work fewer hours, your experience will accrue more slowly. But this is separate from cultural acceptability or value judgments by your coworkers/employer: one can be productive and motivated for 36 hours a week, just as one can be lazy and unmotivated for 40.