1. You have 206 bones in your body. Want one more?
It’s crude and it’s not even clever.
2. I’m calling the police because you stole my heart.
Really cheesy, to the point of being cringeworthy.
3. Are your pants a bit tight or are you just happy to see me?
Confidence is good, but cockiness (no pun intended) is not. The not-so-subtle subtext implies you’re just after one thing, which you probably wont get using this line.
4. You know what would look good on you? Me.
Nobody wants to go out with somebody who has a bigger ego than themselves. This line screams that they are egotistical.
5. Do you come here often?
This line is too ambiguous. Depending upon where you meet, this could have all sorts of subtext. I once had a guy say this to me in the waiting room of a sexual health clinic. I walked on by and thankfully never saw him again.
My advice would be to avoid the one-liners all together. Start the conversation with a simple ‘hi’ or ‘hey’ and stick to genuine complements.