Loblaw/Shoppers Drug Mart pharmacists work on quotas, and the pressure to dispense as quickly as possible causes them to miss obvious and serious drug interactions. The quota system for prescriptions is an actual pressing threat to patient safety.

In BC, if you take more than 3 prescription drugs, pharmacists can bill the province for a medication review (around $80 last time I checked). The medication review is supposed to be a minimum of 30 minutes, improve the patient's treatment plan, etc. SDM would literally turn this into a pure box-checking exercise to claim the $80 in 3 minutes or less.

Oh, and they charge for injecting a vaccine into you (a 3 minute activity and for most vaccines, something you could train a monkey to do). In comparison, independent pharmacists tend not to charge injection fees because they'd rather you come back as a repeat customer than treat you as a cash pig.