What are the three stages of maturity?

Stage 1: Your marmite sandwich is tainted by smears of another family member's peanut butter sandwich, rendering it totally inedible. WHY is it so hard to use a different KNIFE?

Stage 2: Your marmite sandwich has a definite tang of peanut butter, and you wince briefly but eat it anyway. You're lucky someone took the time on a busy morning to make lunch for you.

Stage 3: Your marmite sandwich has a barely discernable hint of peanut butter, and you smile fondly, grateful for the lunch so lovingly prepared for you and other members of your family. In fact, the blend of flavours is subtly interesting.

I am proud to say I am currently sitting at stage 2 and three quarters.