You have probably run across multiple lists that name the top mistakes that are made in specific programming languages, but I came across an article recently that named general programming mistakes that are not specific to any one language. Top Ten Mistakes Every Programmer Makes by Julian M Bucknall was featured in Tech Radar in 2010. Read the article for detailed information about every mistake on the list.
1. Writing for the compiler, not for people
2. Writing big routines
3. Premature optimization
4. Using global variables
5. Not making estimates
6. Off by one
7. Suppressing exceptions
8. Storing secrets in plain text
9. Not validating user input
10. Not being up to date
What mistakes would you add to this list?