You thought about ducks didn't you?!
Apparently we all have intrusive thoughts, they just pop into our heads, which is a revelation to me! I thought I was going mad but that's only when you believe them!!! Here are some common ones from a study by Purdon & Clarke (1993) - by the way - I'm not trivializing other peoples problems or obsessions, however, I found this interesting and a bit of an eureka moment.
When I realised visualizing choking one of your children with their dirty socks after repeatedly asking them to put them away (!) was normal I felt great relief, as I did when I now know I'm not the only one who has an overwhelming urge to jump of high place (39% women/46% men) or removing all dust from the floor (35%W/40%M)
Running a car off the road (64%W/56%M) Accidently leaving the oven/fire on (79%W/66%M) Leaving home unlocked (77%W/69%M) Insulting strangers (15%W/59%M) Swerving into traffic (55%W/52%M)