Alright, that's also a position. But I expect a player to act according to his character's personality. If you play a grim, sullen Barbarian, the character should say other things than if you play a light-hearted jester type.
(Once, in a Shadowrun round, I had to remind a player his character was a 10-foot troll with Intelligence:1 and Charisma:1, after that character addressed another person in-game with something like "Good day to you, dear sir, may I ask you what leads you to this less-than-desirable neighbourhood" or something to that extent.)
Be that as it may, roleplaying awards are only a minor component in my round -- maybe 10% of the total at best. This also applies if the player, while staying in-character, makes the entire group laugh. After all, we do this stuff for FUN.
XP represents the character's development.
Which brings me to another question: do you award XP for failures or bad decisions? After all, you learn from your mistakes.
This is something I haven't done so far, but I consider it an option. Provided that the players made a good effort, and either failed against overwhelming odds, or even if they had a bad plan but learned from their mistake.
Or what about avoiding or fleeing from an overly powerful opponent rather than fighting it out?
Intuitively, this should be only a fraction of the XP you get for outright success. However: suppose you have to steal something out of a guarded manor. Out of luck, you find an extremely easy path. Should this get you more XP than taking the regular path, which requires you to bluff or fight guards, find and disable traps, and make your getaway? The latter is certainly a more intense _experience_.