i have come to learn that there are some people in your life who will relentlessly cheer you on, for better or for worse. and then, there are some who simply will not. no matter what. no matter how many times you beg or plead them to.
being pleasantly persistent is a necessity in achieving anything worthwhile in life. however, if you encounter a negative, condescending, or just plain difficult person -- why spend time with that? life is too short to be spent with negative people. move on. i guarantee that there is someone out there who will enthusiastically, willingly, and cheerfully, appreciate you for who you are and whatever it is you're doing. go find them.
if you're looking for someone to write a letter of recommendation for your grad school application, and your old boss is giving you the run around, telling you how busy he is and listing off the 35 reasons why he can't fit it into his schedule to come up with a few paragraphs (like you've never done him any favors...). just thank him for the time he has given you so far, blow that popsicle stand, and go find yourself an advocate who will do everything short of putting on a cheerleading uniform as she writes you the most stellar letter of recommendation anyone has ever read!
the customer service rep who will not listen to your situation and bluntly tells you that there is no possible way that you can change your flight, or book that room, or exchange that fine item -- fine. don't end the argument getting frustrated because she is "insensitive and callous" and refuses to do what you're asking. hang up. call back until you get someone who is eager to help you.
my point: don't spend time with negative people. we have a CHOICE in the people we surround ourselves with. if there are unsupportive or negative people in your life, whether it's a personal or professional relationship, no one is forcing you to spend your time a certain way. get those poisonous people out of your circle of influence. there are plenty of people in the world who will celebrate your successes, and have your back, watch your dog, cover for you at work, or recommend you for that new job.
you wouldn't bang your head against a brick wall, would you? then why would you voluntarily stick around the people who drain your positivity and curb your success?
go find and spend time with the good ones -- they're out there waiting for you.