Opinion -- a conclusion or belief frequently based (as lawyers might say) on facts not in evidence. Having an opinion is not incompatible with others having different opinions and being respectful and even accepting of them.
Opinionated -- a person (often a bore if they go on and on) who speaks as if their opinions are facts rather than mere beliefs. Being opinionated is incompatible with other people having different opinions.
I enjoy people who hold passionate opinions, certainly much more than people who are wishy-washy and can't make up their minds about anything. However as I have become older, I don't enjoy opinionated people where most conversations turn into a debate that I have neither initiated nor invited. Sometimes I will engage, but just as often I will pacify them superficially to avoid a debate I am not in the mood for.
If you interact with an opinionated person and would like them to just leave you alone, you might try the following:
OP (Opinionated Person): yadda, yadda, yadda (expressing an unsolicited adamantly held opinion).
You: (Pause and then say) Hmmm? (in a questioning tone that begs a question).
OP: What? (taken aback that you haven't caved in and agreed with them).
You: (Pause and then say calmly and deliberately) I was wondering if what you said is just your opinion, which you're certainly entitled to. But if you believe it's fact, I'm curious about your supporting evidence and also what other points of view you haven't considered that might be equally valid?
OP: Huh? (taken aback that you have had the audacity to stand up to them and now speaking to you in a disdainful and offended voice).
You: Yeah, if you believe that what you're saying is the only point of view on that and if you don't have supporting evidence and haven't considered other options, then it is just your opinion and I'll consider it as that and just write off your loud voice as just your way of talking to make your point.
OP: a) You're not making any sense (how they might respond if they are befuddled about how to react) or b) Oh, never mind! (how they might respond if they can't get the better of you).
You: a) Not trying to confuse you, I'm just confused about whether you're expressing an opinion or a fact that I might not agree with or might not even want to hear (at that point they may just say something indignant and walk away ... score point and match to you) or b) Okay with me (at which point they may leave you alone and go bore someone else... mission accomplished in getting them away from you).