Best Big Brother series internationally every year?
 

Starting from 2000 and it can be from any country's BB...

For me:

2000: Big Brother 1 UK
2001: Big Brother 2 USA
2002: Big Brother 3 USA
2003: Big Brother 4 USA
2004: Big Brother 5 UK
2005: Big Brother 6 UK
2006: Big Brother 7 UK
2007: Big Brother 8 UK
2008: Big Brother 10 USA
2009: Big Brother 10 UK
2010: Celebrity Big Brother 7 UK
2011: Big Brother 12 UK
2012: Celebrity Big Brother 9 UK
2013: Big Brother 1 Canada
2014: Big Brother 2 Canada
2015: Celebrity Big Brother 15 UK
2016: Celebrity Big Brother 17 UK
2017: Big Brother 5 Canada
2018: Big Brother 20 USA

the only year I’ve watched all the series has been this year, and I would say BB20

2000: Big Brother 1 UK
2001: Big Brother 2 USA
2002: Big Brother 2 Brazil
2003: Big Brother 4 USA
2004: Big Brother 4 Brazil
2005: Big Brother 6 UK
2006: Big Brother 7 UK
2007: Secret Story 1 France
2008: Gran Hermano 9 Spain
2009: Big Brother 10 UK
2010: Big Brother 10 Brazil
2011: Secret Story 2 Portugal
2012: Gran Hermano 13 Spain
2013: Big Brother 5 Denmark
2014: Big Brother 2 Canada
2015: Celebrity Big Brother 15 UK
2016: Big Brother 17 UK
2017: Big Brother 5 Canada
2018: Big Brother 18 Brazil

This year: BBUS20 (although CBBUS's first season was also a good one)

Can't remember past that

2016 should go to BB Brazil is only for Ana Paula #olhaela

This season died after her ejection on Week 7, but her 7 weeks in the house was probably one of the best seasons ever...

2000: UK
2001: USA
2002: UK
2003: USA
2004: UK
2005: UK
2006: UK
2007: USA
2008: UK
2009: USA
2010: Pinoy Big Brother Teen Clash
2011: Pinoy Big Brother: Unlimited
2012: UK
2013: UK
2014: Pinoy Big Brother: All In
2015: Pinoy Big Brother 737
2016: Pinoy Big Brother: Lucky 7
2017: UK
2018: UK