Well I have my share of friends who work with curses or have cast curses, and I have collected a few over the years but I've never cast one and I don't think I've ever been cursed. There was one time I suddenly felt a ton of negative energy randomly bog me down, and I did feel a couple things that do indicate a curse, but I did a cleansing and it was gone so I don't know if it was one or a random field of negativity.
Curses aren't as bad as many people think they are, and most of the time the curse is self inflicted. Meaning, someone brags about cursing you, you worry, your energy turns dark and poof, you've brought bad things on yourself. Daily shielding and regular cleansings will protect you, and if someone randomly says you've been cursed, just ignore them, maybe make a protection charm, but curses gain strength from energy, if we don't feed it, they go away.