In general I have to agree with Tom. There are physical and mental aspects to self defense and you need both. I have done both Tae Kwon Do and Hapkido and found the mix to be pretty useful.

Tae Kwon Do is usually taught as a sport and is great for getting you in shape and teaching you that you can take some damage and keep going through the pain. Of course that depends a lot on the instructor and how (and what) you practice. My instructor had a very "practical" mindset and really emphasized the defense aspects as well as the sporting ones. Some of the best defense moves in Tae Kwon Do are not allowed in sparring (imagine that )

Hapkido was an eye opener and it was amazing how easily you can seriously damage people with very little effort (in the moment, learning is a lot of serious sweat and pain). Great for practical defense and scalable from let me help you walk with me to let me leave you lying there in serious pain or worse.

I had the same instructor for both ( 6th degree black belt in these plus judo) and he was very clear on the difference between sport and defense - same skills, different mindset and you have to practice both ways or you just end up annoying your assailant.

- Eric