Here's a quote from Notch, the creator of Minecraft, which should be a guideline how to do proper achievements:
Achievements will NOT be chores like “cut down 10000 trees”, but rather challenges like “ride a pig off a cliff”.
The achievements can be fun if they need a strategy to be fulfilled (like living an Explosion and using Counter to KO the Pokémon coming after it), however, something like "catch 200 Pokémon you fished" or "Gain 1000 levels using the Day Care" are simply a boring waste of time.