I will gladly close my question if it has been asked before, thanks!
Deletion is never encouraged. Even if the content is bad, you are encouraged to try to fix it, and others will always try to improve it. If it's a decent question but not a good fit for the Q&A format, it'll be closed to prevent further answers. Only if it's not salvageable will deletion become an option.
Keep in mind that as a programmer, your problems are the problems of others. I'm sure many of the problems you've faced aren't unique to you and your situations. That's the concept of Stack Overflow (and SE in general): encountering specific problems and finding solutions that will benefit the programming community as a whole.
If you're only here to get solutions to problems and don't want others to benefit from them, you are always able to delete a question from its page. But I urge you to consider whether this site may be for you if your attitude towards the website is one of self-benefit.
(I don't know why you'd want to delete helpful answers, though.)
That's a ... bad idea.
Why should we give users the ability to do something that is harmful to the ecosystem? You make things easy that you want the users to do. I don't think anyone wants to make it easy to remove content from the system. That's counter to the idea of a knowledge exchange.