After testing the pineapple juggler perk I couldn’t find anything useful about it. Fragger will almost always cook a nade atleast some what making it nearly impossible to use against him. So I thought it could be very useful maybe against nader (especially since its free nader week right now) but you are not able to throw back her grenades 
Pineapple Juggler perk thoughts
elburko
(elburko)
#1
watsyurdeal
(watsyurdeal)
#2
I think that every card that has it should just get Unshakeable instead.
Vexed
(Vexed)
#4
I shudder to think what this would do at the low end of the skill pool, though. I have an iron Proxy loadout with Hochfir, MP400, Tryhard and Pineapple Juggler. I don’t want to imagine what happens when Proxy can buff herself to 120hp with 20% explosive resist and double automatics. It would be really, really messy.
No, it probably wouldn’t be good in high-end play (die once and your buffed hp vanishes), but spare a thought for us terribads, hey?
Old_Man
(Old Man)
#5
One of the worst perks in the game. I haven’t seen anyone ever use it successfully.