Over my life, I have done this, often, for family and love interests. Here is my outcomes...
After homeschooling my oldest daughter for 7 years of her ADHD period (when others turned away from her), paying for her to attend college for a year to get back her financial aid, and letting her stay rent free in my house for 2 years, she stormed off upon me asking her to get a job and refuses to talk to me.
After my first wife left me to do the housework and homeschooling, alone, for years and after I took care of her, too, upon her having a psychotic break, as well as our new born child and finished a degree and got a job to cover bills, my ex has spent the next 10 years vindictively trying to make me look bad to her daughters and even my own mother, who she visited twice after divorce .. just to make me look bad...and attempted to steal 3000 dollars of VA refund money from me.
Recently, my current wife ... while not intentional like the others, received my gifts of selling my house to pay for the wedding, all the dates over years of dating, my strain of having to pay for her courts and move the family back to Oklahoma, after her ex sued to bring us back from Dallas... now, has no interest in me and dislikes me help for her.
In this case, as I said, it is not intentional and is understandable due to her disability making my help be interpreted as her weakness. However, that only makes the case clearer. EVEN IN THE CASE OF FRIENDS, what you give out does not result in respect or gratitude but scorn.
So, enjoy your time with others, but do not ever give up your own foundation or joys for them. You might just find yourself empty, injured, and alone, while they all go off to enjoy others and their lives.