> Even my mother does this in spite of my persistent requests for her not to because she feels an obligation to do so in spite of my pleas.
Oh dear, this is a really dangerous conflation of 2 different practices. You really ought to distinguish for everyone here instead of trashing the whole culture. You're not talking about the same thing others are talking about. Taarof'ing (pretty literally: "offering") can mean multiple things, and it's critical to distinguish them:
1. Offering things expecting you to refuse them. You know, like you go to pay for a purchase and a shop owner pretends to refuse the payment. In such cases, they would be offended if you accept their offer.
2. Offering things in general (generally food...) because they've just been trained to by the culture. In this case, they're "worried" something negative might happen on your end if they you don't take their offer. (You might be offended, go hungry, not have a place to sleep, etc.)
Foreigners talk about #1, but you're talking about #2.
And these are VERY different things.
Your mom making you sandwiches (effectively forcing you to eat them) is NOT #1. She is NOT offering it to you expecting you to refuse it. (At least not due to taarof; if she might have some other beef with you that's another matter.) If it's either of these, it's #2. And in all likelihood, it would be only partially #2—a lot of it is just her being your mom and being overly enthusiastic (obviously some cultural part to this too) about making sure you're well-fed.
However, foreigners care about #1—about offending the person making the offer by accepting the offer. Your mom is emphatically NOT going to be offended if you take the sandwich. Like the native making a sandwich for the person you replied to, she is much wants you to take it and is 100% sincere in that. Heck, she'll be offended if you refuse it!!! Unless I guess, you know, she's doing this for the 500th time and she's hoping you might finally start making the sandwiches yourself, but again, that's only because you're her kid and she wants to see you improve in her eyes, not because of the taarof tradition...