(Strip Number 790, Original Publication Date, 25 January 1985)
Panel 1: AS Phil and Georgia leave the house, Elly tells Michael that Phil isn't mad at him, just disappointed.
Panel 2: As a scowling Phil looks on (shut up, Phil's face!), obviously ungrateful and positively not overwhelmed Michael says it's not his fault he doesn't practice because he's got 'other stuff' to do. (Said other 'useless' stuff that he shouldn't waste his time on is more than likely to be the math homework he also can't wrap his brain around.)
Panel 3: Besides, trumpet practice is too hard a slog in the first place.
Panel 4: Phil looks over the corner of the door with a shocked look in his face when Mike says that he wants to play something easy like the violin or piano.
Summary: Phil seems to have a character defect most 'good' teachers in the Patterverse have: an inability to see that the children around them think that they were born good at their subject matter. Since Mike doesn't see Phil practice, he doesn't realize or appreciate the value of the hard work he doesn't know Phil put in. Also, Phil seems to have had the ability to remember that children perceive time as flowing far more slowly than he does surgically removed.