Saved by habit
I don't make the simple mistakes very often these days, that's what makes them all the harder to find when I do make them. I try to clear my mind and assume anything could be wrong when hunting problems, but its so much nicer where the computer can point them out in the first place.

if (1 == a) { ... }

People give me a hard time for writing code this way, but there's a very good reason to do it like this instead of a == 1 .   Slip up and type a single equals and my code becomes invalid (in just about any language), slip up the other way and you have the perfectly valid but wrong a = 1 . So I had to smile today when the compiler complained to me:

g++ -g -Iinc -Wno-multichar -D_DEBUG -D_LINUX -o obj/snp_core.o -c snp_core.cpp snp_core.cpp: In function `int main(int, char**)': snp_core.cpp:43: non-lvalue in assignment make: *** [obj/snp_core.o] Error 1

Hadn't made this mistake in several years, but a few seconds later the problem was corrected. Somewhere else someone is cursing their program and it may be some time before they find the problem.  ¶ 10:00 PM