DY: I’m well aware of the arguments, and you can even say “inherently better” (Rav Moshe basically did). What you can’t say is that because that person doesn’t keep it, you have some maaleh over them, OR that they should start.
Aderabah, (IMHO) you (specifically, not just someone who has a chumrah) should feel “accomplished” (a better word than “smug”) as someone who is fulfiling their tachlis in life. We were put here to work, and those who work deserve to feel good about themselves. Of course, you don’t know what the other person’s nisyonos are, so they may have completed their tachlis as well (even if they are a mechalel shabbos), but you can feel good about your accomplishments.