Use object-based interactions, if you don't want to affect relationships.
Like, for Flirty, any Interaction that has a pink section on the left of the interaction button counts for that daily task.
So an easy way to get this done would be to queue up "Practice Pickup Lines" in the mirror and cancel it out as your Sim starts to do it.
Just do that 4 times and you should be at 100% for that daily task.
This also works for other emotions.
To do Angry without hurting your relationships, do angry object interactions, like Kick Trash Can, Stomp Trash, or Stomp Puddle.
Playful is also easy, just make funny faces in the mirror over and over, though it's not like playful interactions are that bad to use on others, what with many of them giving positive relationship boosts.
Just make sure you're looking for interactions with the colored section on their icons, like this:
https://puu.sh/CnMa7/e302bd7cb6.png
Hip Bump for the Punching Bag has a pink tag on the left side, showing that it's a "Flirty" action, so this would count for the Research Flirty emotion as well.
