Top ten reasons why we smoke two joints:
#10 They mate for life
#9 1 is lonely, and 3 seems greedy
#8 One good twist deserves another
#7 Too stoned to count to three
#6 Better safe than sorry
#5 Why not?
#4 Every doobie needs a brother
#3 We forget we smoked the first one
#2 It makes us feel allright
and now (drum roll 2 joints please) the #1 reason we smoke 2 joints...
#1 High Tolerance!
rotfl