The OP and many people in this thread are looking for reasons to get upset.
But the latter is the situation here–presumably she knew about when he was coming home and he is not “late”. I think she should have waited, partly because I consider breadsticks part of the meal, and partly because it would be considerate given that she knows how he feels about it.
No, you don’t understand… “Three of the Breadsticks” is his dog!
I was raised similarly. Not the 6 o’clock sharp thing but generally organized dinners, please, thank you, may I be excused, don’t start until everyone is ready, etc. When I met my wife and started frequently eating with her family, I noticed they didn’t do this. I thought, “cool, I always hated that shit,” and did as the Romans do.
Sometimes my upbringing comes a’hauntin’ in the back of my mind, so I know where you’re coming from, but let it go. Or save it for Thanksgiving and other formal dinners. Don’t fight over 3 breadsticks if you want it to last.
Was there a timeline issue? You gave her the $20 for the pizza so it would be there when you got home. How long after the pizza arrived did you make it home? 15-20 minutes, or did you have to wait for the pizza delivery guy to pull out of the driveway before you could pull in?
Sounds like she waited for you, but the luscious smell of the pizza treat got to be too much for her, so she ate some breadsticks. If that’s the case…then I go with RNATB…eating before everyone is served is rude. Eating before everyone has arrived…not so much.
BTW…you can make more money working as a server in a sit-down restaurant than you can at a McDonald’s. You might want to look into an area Outback/Cracker Barrel (those places are insane on Sundays)/Applebee’s, etc.
I’ve never in my life turned away a meal because I snacked first, and no, I’m not obese. 5’8", 162, weighed 30 seconds ago. Go ahead, call me a cow. Maybe it’s from my poor college days when I only ate once a day, or maybe it’s my military experience when I was willing to eat whatever I could get, anytime. I just can’t imagine ever saying “I’m not hungry” just because I had a snack. That snack would have to be huge for me to turn away a meal.
I’ve had those situations, and think that it’s a heck of a lot more rude to make people wait a long time for the food that’s already ready than it is for a person to snack on a small amount of a side dish/appetizer before you get there. I’m more likely to wait until you get here to eat/cook than to just serve something up for myself when I know I’m waiting for you as well, so making me wait until I’m hungry and cranky and tired just makes me more likely to piss you off while being angry at you. This is partially my fault, but it’s also a miscommunication error as the other party seems to assume I’ll dig in if they’re an hour or more late with no notice that they’re running later than they’d hoped; If I don’t know you’re expecting me to start without you, I won’t do it.
If it’s an issue that the girlfriend not eat anything before you get home for the meal, then don’t ever be late. If you relax about her snacking on a breadstick or two, then this wouldn’t be as much of a problem.
Hell, I’ve been known to eat a slice of pizza while driving it home. My wife thinks it’s funny. Maybe I’m an uncouth barbarian, but at least we don’t go into a tizzy over some damn breadsticks.
But again, I think that part that pulls it over into Rude is that they’ve discussed it before and she knows how he feels about it. Now, she can decide whether that’s too control freaky to stay in a relationship with, but while she’s there surely she can respect his wishes, if he has also compromised to meet her tastes.
I see where you’re coming from on this, but I also think the breadsticks might be a compromise of sorts … if she was very hungry, she might have thought about having a slice of pizza but then remembered “gee, my BF feels so strongly about having the meal together … I’ll just have a few breadsticks to tide me over until he gets home.”
I guess we don’t know if she was eating because … she was bored and tired of waiting (really pretty rude, IMHO) or if she was genuinely hungry and felt she needed to eat something (not rude, IMHO). I probably feel so strongly about this because I picked up some weird food issues in childhood, but I think it’s perfectly okay for an adult to determine if he/she is hungry, and then eat something in order not to be hungry. I’d be very disapproving if she ate an entire dinner without waiting – that’s RUDE – but sitting around your own house being uncomfortably hungry is unnecessary.
I think he may have been disoriented by the clean bathroom. Prolly since I cleaned all the spit-and-toothpaste spots off the mirror he could see himself for the first time in a year and it was like infinity and he curled up in the corner sucking his thumb or something.
I, uh, hauled four bags of trash out of the bathroom. No, it’s not a large bathroom by any means.
I feel the same way when I cook a meal and my husband doesn’t come to eat when it’s ready - I just cooked for an hour, you can come back to your post later, after we’ve both eaten, is my thinking. It does feel disrespectful to me - like he is taking my efforts for granted. He doesn’t do this often, though; I think he got the message that I appreciate his coming to dinner promptly. 
Captain_C, I don’t think you’re as out of line as some people here, but I do think this is something you and your girlfriend should hammer out, because there is obviously more to this than her eating three breadsticks. You say that she knows this is a peeve and she should be more careful with it; you’re not wrong about that, but she’s also an adult and doesn’t have to do things your way just because it’s a peeve of yours. You do need to find a compromise you can both live with, though.
For the record, I eat many small meals throughout the day, and three breadsticks would make me very close to full, so those of you saying she just had a bite are not quite correct - she had most of a meal, for a small eater. And for their circumstances, the pizza was an event.