I. After if, we normally use the present simple for the future (if I do/ if I see etc.) (e.g. I'll be angry if it happens again. (not if we will go))
I1. We use if (not when) for things that will possibly happen. (e.g. I might go shopping later (it's possible) If I go shopping, I'll but some food.)
a. We use when for things which are sure to happen. (e.g. I'm going shopping later. (for sure) When I go shopping, I'll buy some food.)
Idiom 365
Fixed In Your Ways: not wanting or willing to change how you do things
Example: It is very hard to accept in many times that previously experienced people are fixed in their ways.