Thou shalt not waffle
Stressful situations generally, and roleplaying games particularly, bring out the cautious multi-taskers in everyone. Unsure of their course, players flit from plan to plan as the urges strike them. Play by email, where players can brood for hours on a single post, makes this much worse. I've seen people asked for a firm, "yes or no" decision say (essentially) "Yes... but then again no... or rather, it depends... which is to say no... unless yes would be better."
I'll let you in on a little secret: Almost any decision, followed up forcefully and with determination, will be better (both in-game and in terms of drama) than waffling. Waffling is evil, a sin. Don't do it.
Beware particularly the time-distributed waffle. You decide "Yes, it is worth invading Amber, even though I know full well it will be difficult". Then when it gets difficult you say "Maybe I'd be happier on vacation in the Bahamas". I don't want to stop people from reacting to changing circumstance (suddenly Amber is under Chaos attack, so you turn your invading army into defenders), but I hate to have a good drama defused because people simply lose their nerve.
Remember, when you give up in the face of resistance you are telling the world (and more importantly the Family) that your character is a quitter. Who's going to respect a Prince of Amber who they know will turn and run at the first sign of opposition?