So, I look at the proposal as a final exam for the first stage of a relationship. If you've paid attention, asked questions and really processed the material you will pass with flying colors and it won't even feel that hard. If you're a lazy slacker you won't do well at all and you shouldn't be allowed to take Relationships 201: Engagement.
A proposal is a test of the proposer's knowledge of the proposee. You are the professor. You, and only you get to decide the right answers to the test. Not the proposer, not your family, not your friends, not randos on the internet. Nobody gets to judge you about what you want, even if they would hate it. This is about your future.
I don't care if you're apathetic to particular circumstances or if you're a controlling bridezilla to be. This is a test about compatibility. Can your future spouse recognize your needs and desires? Are they capable of doing so? Do they want to do so? Will they set your wants aside for you for ONE night?
As they are the one asking, you havepresumablymet their standards for a spouse.
Did they take you somewhere meaningful to you? (Not necessarily expensive. If it's meaningful for you to be asked on your family's porch swing, then that's where it should happen.)
Were you comfortable with the environment? (Some people want it to be private, some with family, some in public.)
Did you have the amount of input into the process that you wanted? (Did they surprise you? Did they catch your dropped hints? Did they baldly ask you?)
Did they make the right choice for your ring, or did they disregard your likes in favor of their desires? (Size? Price? Materials? Workmanship? Sentiment?)
Was their manner what you wanted? (Down on one knee "will you marry me?" Tossing you a ring box "wanna get hitched?")
If they failed to give you the proper answer on any of these questions: there is a problem in your relationship and you MUST diagnose it before accepting.
Why did they ask in the wrong place? Because they liked that location more than the one you wanted? (Very bad. They can't even put their wants aside for one night to butter you up.) Because they asked your best friend and she chose wrong? (Minor communication issue. Possibly overvalued the surprise aspect. This is fixable.)
Why did they ask you in private when you wanted something public, or the reverse? (Fairly big problem. This could be down to a lot of different factors, including a mismatch between introversion/extroversion. But it could also be manipulation to see if you'll accept something they know you don't want. If they're an introvert and you're not, will you be happy not being in the spotlight that they avoid? If you're the introvert, can you be with someone who drags you into situations you hate?)
Why didn't they listen when you flat up told them what you wanted? (Inattentive? Don't care about your desires? They don't know how to read your "obvious" hints? All bad things. At worst they don't actually care. At best communication needs work.)
Why did they get a ring you hate? (Too cheap to buy better/Refused to buy something cheaper/couldn't afford it? Very bad. You're dating someone with a different financial philosophy than you or a different bank account than you require. Aside from abuse this is actually the worst issue to have. Financial incompatibility will make your life hell. Break it off. They thought you would like it? Communication issues/unobservant. Work on them some more. The salesman told them it was fine/what's wrong with the material/craftsmanship? Uninvested in the process, uninterested in educating themselves on an important item that should last a lifetime. Not great signs in a life partner. What will they do when you have to buy a house or a car? They have remedial work ahead. )
Were they too formal/casual when they asked? (They don't have the same level of emotional investment in this that you do or they have different standards for behavior. Run away from the first immediately. For the standards? Can you live with their attitude towards life being so different from yours?)
You can diagnose a lot of problems in a relationship from a bad proposal.
The fact that this guy picked a shoddy ring of cheap materials and then lied about it? AND failed to get it resized? Instant failure of the remedial course. Buh-bye. You're no longer a candidate for grad school.