Page 456 - Makino,Tsutusi.DictionaryOfIntermediateJGrammar

382 sei

I. Okage and sei are similar in that both express a cause. The difference is
that okage is used when the result is desirable, as in [I]. Note also that
okage implies that the person who attained the result is thankful for the
cause.
bWt, kt
[I] a. a~)bb~&fi>(fT@flrttld~-31:o
(The safety belt saved my life. (lit. My life was saved
thanks to the safety belt.))
b. @kflFIZ-3 T < ;k7':&fiW'lrf~~~flg < g&11:~
(Because she helped me, I could finish my work quickly.)

(Because I studied English hard when I was a student, I
don't have much trouble with my life in America now.)
Okage is sometimes used with an undesirable result for the purpose of
sarcasm, as in [2].

Itl.+< El., b
z
b. S~fl&&fh 2 2 LT < ;kk&fi>(fT$+j@fl&@ LG:@
-3 ?z0
(Because you did something unnecessary, thanks to you,
our plan was ruined.)
11. Tame (ni) can also express a cause (as well as a reason), as in [3].

Unlike sei, tame (ni) has no such restrictions as those in Notes 2,3, and
4. (+ tame (ni) (DBJG. 447-5 1))