Yes, many times.

That's because people with predatory nature know it when they spot someone with doormat attitude. Few incidents I can think of are

1. My roommate and another acquaintance who had vested interest in bringing me down, shared twisted stories about me to peers so that they can have a better image. Im generally helpful and I thought people wouldnt believe. Hell No. These are the toxic negative people whom you should not keep next to you. Howmuch ever good things you do, bullies and gossip mongers will not change until you stand up or take action.
2. A friend of mine would come and stay in my apartment once in a while. I'll make breakfast for her and let her use all my stuff. It was like bed and breakfast for her without having to spend money. All she did in return was take me to a cheap restaurant and call me a cheap person because I ordered simple food. she doesn't respect preference of others. When I confronted her, she slowly disappeared from my life.
3. My roomies would not be available to clean up the house, empty trash, etc but they would be ready to pass comments on me or pinpoint mistakes all the time. I slowly cut off these useless people.

I was stuck with the thought that 'i have to be kind and helpful to everyone' and people will change for good. But these toxic negative useless people never changed. It took several years to realize that the one supposed to change was ME. Stand up for yourself and be more assertive. You will lose all the people taking advantage of you because when things are not favorable for them they look for another doormat person. Let them go. Your life is going to change positively.