I am re-watching Breaking Bad for 2nd time and I observed that the first time in whole series when Walter makes sandwich is to feed Krazy-8 in basement. At this instance, he gives sandwich with breads having crust. When he sees Krazy-8 tearing off the crust, next time onward, Walter himself cuts off the crust before giving it to Krazy-8.
Later on in series, when he separates from Skyler, he is again shown making sandwiches for lunch while working for Gustavo. At this point, the scene is focused on Walter's sandwich making. Thus, showing him cutting the crust as he used to do for Krazy-8.
Usually a person also serves a person food in a way himself likes it. For example, Walter likes to eat bread with crust. That's why he serves Krazy-8 with sandwich with bread crust. So is the change in Walter White's bread eating habit related to Krazy-8? Can this whole thing make sense?