Took our first cruise together in 2009 and have been on 7 since then (8 if you double count a back to back). Our vacation of choice, RCCL and Celebrity.
Next voyage is on the Reflection in December, though keeping our eyes open for a last minute fare out of Seattle for the week of July 4th if we can. Booked some award tickets on Southwest, so if we cancel no harm done.
Love Celebrity, though we've found friends of Dorothy hit or miss, it's really about the venue, when you board check the message board, if it's in a secluded venue, write up a card and place it overtop to change it to a bar that fronts an active area. i.e., on Celebrity the Martini Bar (or Molecular Bar on S Class) will get a better group going. Somewhere like Michael's club is set aside, and it is awkward to hang around if no one has shown up yet.
The key is there is people watching and it's not awkward to be waiting for people you've never met....we're such a punctual group!