Title says it all.
I've been playing League, albeit on and off, since season 2.
I must admit, I no longer have much time to play. Not as I used to.
When I have time for only one single game in the evening, I'd rather play a single game with my friend without the stress of having to win at least one game to win the first win of the day bonus.
Sometimes I just sit back and play bots to be sure that I'll have at least that win in the bag.
If I could play PvP without the stress of winning that single game, I wouldn't mind testing my luck and playing normal games rather than playing co-op vs AI.
The difference in exp between a win and a loss is small, ( assuming a Summoner's Rift 30 minutes game, it's 204,6 for a win vs 167.4 for a loss, W-L=37,2 exp ), but the 400 exp when you first win makes a huge difference, as it nearly triples how much exp you win when you only play one game.