C++ FAQ Celebrating Twenty-One Years of the C++ FAQ!!!
(Click here for a personal note from Marshall Cline.)
Section 25:
[25.3] So there are times when multiple inheritance isn't bad?!??

Of course there are!

You won't use it all the time. You might not even use it regularly. But there are some situations where a solution with multiple inheritance is cheaper to build, debug, test, optimize, and maintain than a solution without multiple inheritance. If multiple inheritance cuts your costs, improves your schedule, reduces your risk, and performs well, then please use it.

On the other hand, just because it's there doesn't mean you should use it. Like any tool, use the right tool for the job. If MI (multiple inheritance) helps, use it; if not, don't. And if you have a bad experience with it, don't blame the tool. Take responsibility for your mistakes, and say, "I used the wrong tool for the job; it was my fault." Do not say, "Since it didn't help my problem, it's bad for all problems in all industries across all time." Good workmen never blame their tools.