In this UK Telegragh article by Linda Blair, Angela Buttimer is quoted:
“As Angela Buttimer, a psychotherapist in Georgia, put it, ‘When we hold onto grudges and resentment, it’s like drinking poison and expecting the other person to get sick.”
Check out the entire article: https://www.telegraph.co.uk/health-fitness/mind/holding-grudge-can-make-let-go/