Common bugs categories I’ve run into over the years:

• Customer to me: “I told you to do that, why didn’t you?”
• Customer to me: “I didn’t tell you to do that, why didn’t you?”
• Customer to me: “I didn’t tell you to do that, why did you?”
• Users to me: “wow, this part of the app really sucks”
• Me to computer: “Why did you do exactly what I told you to?”
• Computer to me: “wow, you really can’t do simple math, can you?”
• Me to computer: “why are you so fast and capable of doing 2-8 things simultaneously?”