Well, I promised a longer response over a month ago, I guess I better get to it then.
I voted for all except the bottom three, and I will explain my reasoning to each one.
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Flirting is silly - If it has no purpose behind it, I think it's a bit silly, or if it's silly pickup lines
Flirting can be dangerous - If you have a partner (bf/gf, fiance, husband/wife) and you're flirting with other people, that can be very dangerous, for obvious reasons
Flirting can be distracting - It can be distracting for those involved and for others around you. If you're in a Bible study, flirt afterwards or somewhere else and let the focus be on studying God's word.
Flirting can be overdone - Some people just don't know when to stop, and it can get annoying
Flirting is fun and can be beneficial - It can be fun, especially if you both like each other. It can send signals that you're interested, which can be beneficial
Someone who flirts can be faithful to one person - You can flirt within a committed relationship with the other person. Or, someone who was a flirt before can then direct all their attention to the other person
Someone who flirts may have trouble being faithful to one person - Despite my answer above, I also believe this can be true as well. If someone is flirty with everyone, then that makes me question their motives behind flirting. Is it for their ego? For attention? Will they be able to not be flirty with other people while in a relationship with someone else?
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To sum it up, it depends on each person's individual situation and motivation (are they in a relationship? Are they trying to send a signal or just wanting positive feedback to feed their ego?)
As for the last three, it depends on someone's motivation on whether or not I want to be flirted with. I'm pretty bad at being able to tell if someone's flirting with me, though. It hasn't happened enough and I really only can tell if it's super obvious. I don't know if I know how to flirt. I think so? That's probably a sign that I don't. Ha.
I'm the same way and apparently I don't realize that I flirt, a friend will tell me afterwards that I was flirting and I'm like, when did that happen? I guess being friendly means flirting or something. It's very strange. lol
To address this, I recently read a quote that was something like "What kind of sad world do we live in when politeness is regarded as being flirted with?" Sometimes people can misread things, but what's sad is that our world can sometimes be so cut-throat and uncaring that when someone DOES care, we think it means something more.
I feel like I just wrote a book with this post, it seems long. And it's funny that I wrote such a long post on something I don't know much about.