Start doing some experiments. Take your phone to Starbucks and see if, on Starbucks WiFi, if you have the same problem. If you have the same problem, attempt uninstalling the application (press hold, hit X) and reinstalling it. If you aren't having the same problem, I'd suspect something on your network at home is needing some maintenance. For example, we had some neighbors move in and they got Charter Cable. This made our 2.4Ghz WiFi unusable - so I had to change the channel that ours was on.
It depends on the devices too - 3-5 seconds isn't much to be worried about - depending on where that person is or what device they have.
Spamming can have a "squeezing" effect on the ability to send stuff too - to prevent users from DOS'ing their services.