SSIA.

Whilst not a "collector" countries, making a list was interesting.  I'm not 100% sure it's complete, but certainly close.  I feel old when I'm beginning to forget visits.  I count 35 (33 if UK is regarded as one):

Norway (native), Sweden, Denmark, Finland, Iceland, England, Scotland, Ireland, Northern Ireland, Germany, Poland, Czech Republic, Slovakia, Netherlands, France, Austria, Lichtenstein, Switzerland, Slovenia, Italy, Spain, Greece, USA, Canada, Peru, Brazil, Uruguay, Argentina, India, South Korea, Japan, China, Singapore, Malaysia, Indonesia.

Maybe a couple of more if I count countries in which I've just been through airport transit.  Portugal, I know.

Most visited countries, at least 5 times: Sweden, Denmark, England, Ireland, Czech Republic, Austria, USA, Japan. 3-4 times: Finland, Germany, Netherlands, France, Spain, Italy, Slovenia, Canada.

South Korea, Japan, Philippines, Hong Kong, Singapore, Sri Lanka, Kenya, Diego Garcia, Spain, France, Italy, Israel, Turkey, Germany, Nigeria, Czech Republic, Canada... one more I think.... Oh yeah, These United States of America.

Just four so far: The US (native), Canada (numerous times), Bolivia (twice), and Peru. Across the US I've visited more states than not, and driven across country (Virginia to Washington) twice.

Across the US I've visited more states than not, and driven across country (Virginia to Washington) twice.

US states for me are just New York, Connecticut, Rhode Island, California, Florida, Oregon, Illinois, Hawaii and Tennessee (airport only).  Places visited in Canada: Nova Scotia, Newfoundland, Montreal, Chicago, Calgary.

I have been to Australia in 2017 and I have visited Canada (technically). For Canada I went on one of those boat tours that crossed a maritime border. Not quite visiting, but it technically counts.  

4 Countries: UK, US, Poland, and Russia. All of them have their similarities and as well as advantages and disadvantages. All of them are great, despite my homeland England is slightly better

Ive been to 4 countries including my own. Germany, Poland, Finland, and the Netherlands

8 countries including US:) Italy, Spain, France, Germany, Argentina, United Kingdom and Mexico