This thought just occurred to me today.  There is actually a benefit to not always getting what you desire manifested instantly.

The reason being - it is an opportunity to develop your "faith muscles".  Faith doesn't always come instantly.  And Faith doesn't necessarily come from having a desire instantly manifested.

The Faith comes from having a desire, then getting through that gap of time from having the desire to manifesting it - yet all the while before it shows up believing and knowing it WILL SHOW UP.

Once you get Faith, you just have it.  You really only have to learn it once.  After you experience developing Faith and knowing you can trust it - then subsequent manifestations can come much quicker.  Or at least the time between asking and receiving feels better.  There isn't doubt - just knowing with ease that it's coming and the only reason it is taking time is because the Universe is lining it all up to be delivered perfectly.