Much of your problem can be solved with one simple word...NO!
"Conan! Bring your truck over and help me move this weekend."
NO!
"Conan, these flowers are okay, but I really like those $25 dollar orchids. Buy me one!"
NO!
"Conan! Dude! I'm short on cash, pick up a case of beer for me!"
NO!
"Nice" guys let everyone walk all over them, let their girlfriends run their lives & never say a word about it. The instructions to being the captain of your own destiny is found in the DJ Bible.
You don't have to be an ass about it, but saying "NO" now and then will make people respect you a little more.