The Doctor is a Time Lord: a 900 year old alien with 2 hearts, part of a gifted civilization who mastered time travel. The Doctor saves planets for a living – more of a hobby actually, and the Doctor's very, very good at it.
Doctor Who is my favorite show ever. It's not perfect, but it's exciting, fun, witty, creative, and quirky. The best way to watch is with an open mind and with (preferably) a good episode. Sometimes it can get cheesy or too silly, but as whole it's an amazing show. Series 11 starts next year with Chris Chibnall as the new showrunner and Jodie Whittaker as the new Doctor, and it's gonna be fantastic. God bless Doctor Who!