I dated one. Got clingy, paranoid, controlling, and would die if we spent a day apart. Probable BPD.
Had a good friend in high school who is likely an INFP. He's also a two faced, inconstant, backstabbing prick. Very dependent on the wrong people and quite unhealthy.
Have a friend from before high school that is likely an INFP. Completely harmless, wouldn't hurt a fly, very much sensitive and overall a pretty decent guy. Bsc in physics of all choices.
But overall, I think INFPs are rather nice. Total sweeties.