How do I impart "extra" flavor with Sous Vide cooking?

How do I impart "extra" flavor with Sous Vide cooking?

I've been cooking Sous Vide 2-3 times a week for about 10 months now, and
I absolutely love it. The control of temperature and time makes for some
really interesting possibilities. But, one of the touted benefits of the
method is better imparting of flavors during the cooking process, and I'm
not getting this at all.
I'm not using a vacuum sealer in my process, instead I'm submerging an
open bag in water and letting the partial pressure get all the air out
before closing it up. Is this the reason I'm not noticing the additional
flavor? Do the muscles in the meat need to be stretched by the vacuum? If
that is the case, is a home vacuum sealer sufficient for that? I somehow
doubt that a vacuum sealer gets much more negative pressure on the meat
than my method. Do I need a chamber vacuum to get the effect?
Or am I just not using the right ingredients in my recipes?
What am I doing wrong? I love my Sous Vide Supreme, but I feel like I'm
missing out on a piece of the experience.
Edit: I tried looking for some of the recipes that I haven't had luck with
last night, but because everything is mostly google searches, I couldn't
really come up with anything concrete. However some things that haven't
really added that extra flavor are: Olive oil, butter, bacon fat,
rosemary, thyme, and garlic. Not all at the same time, but in different
combinations. A lot of my initial reading was careful to point out that
you shouldn't use too much seasoning as the tastes would be much stronger
than you were used to. I'm not getting that at all.