That is why I dislike McD's, they put so much sauce on everything that I feel like I am drinking the sandwich! I do like their tartar sauce but even that drips out of the fish sandwich. Needless to say if we eat there I always order the fish sandwich.just a quick sandwich note...
the basic sauce that McDonalds uses on burgers is really just a combination of mustard, ketchup and mayo. If you play around with the combo, you will probably find a nice sauce for yourself. My guess would be to start around 1 tsp mustard, 4 tsp of ketchup, and 4 tsp of mayo...
see how that works and adjust it from there.