Capital One screwed me over when I had a credit card with them about 25 years ago. It was less than $100 but I never forgot. The day they announced they were buying ING is the day I moved my money elsewhere.
I'm sure they've lost far more by losing my business than the money they squeezed out of me years ago.
They feel skeezy, from years of marketing and targeting of their credit cards. I liked the ING Direct branding before CapOne bought them. No specific issues or experience though.
I got screwed by Capital One when they refused to wire my funds to a different institution when I needed them to for a big stock option exercise. The rep on the phone told me their policy was to only do wire transfers for home closings. They wouldn't budge, which seemed shocking and completely unacceptable to me, so I initiated closing of the account that same day.
I'm sure they've lost far more by losing my business than the money they squeezed out of me years ago.