These grab bags, along with almost constant spam across the screen about people winning (odds are great, play now!) are frustrating, annoying, and take you out of the game. And just generally leave a sour taste in your mouth when it should be one of the best times since initial launch...
If you think that's bad, wait till you see what some other MMOs have done to drive customers away.
F2p-wise, EverQuest 2's is probably the worst of the bunch where anything beyond the most basic gameplay is locked behind a pay wall.
The most memorable one for me is the infamous EverQuest Gates of Discord saga that caused me to stop subscribing to MMOs for several years. Imagine you and your 100 strong top end EverQuest guild have just spent a year working really hard to unlock the best possible gear the last expansion pack had to offer. You and your guildmates now own the absolute best possible gear the game has to offer. Now SOE releases a new expansion pack called Gates of Discord and suddenly every single top end guild including your own get their asses wiped by the very first, weakest raid boss in the new expansion pack. Now imagine how the entire playerbase feels when the best of the best players are getting their asses wiped. During the first three months, I saw corpses everywhere in the new expansion pack. I think at least a quarter of the playerbase, including many top end players, simply quit the game en masse and the CEO of SOE had to publicly apologize and promise to tune things down.