Getting right back on can be fatal mistake. When I was T-boned on my '04 I was on my feet immediately, ready to attack the guy that hit, but 4 cops witnessed it, and they were there before I got to him. The paramedics checked me over, let me pass on the ride to the hospital, but told my wife to watch me closely. 2 hours later I passed out (low blood pressure from massive internal bleeding). If I'd been on the bike then, I'd have gone down again, probably to never get up again.
But waiting for the right time can be nearly as bad. I bought my '05 with the insurance payout. I didn't know a single person that understood why I wanted another bike, but I knew if I let them talk me into waiting, eventually they'd talk me out of getting one altogether. So I pushed right from day 1. The accident was in mid-August, and I didn't get my cheque until mid-October, so I basically rode until my 600 km service, then had to store it for the winter. So I didn't REALLY get back on for 8 months after my accident.
This wasn't my first get-off. I've riden dirt bikes all my life, even tried trials riding. And I've raced bicycles (road racing, triathlon, and mountain biking). I've been bucked off hundreds of times, but almost all of them, and all of the serious ones, can be attributed to: another driver/rider doing something unexpected/stupid; loose gravel, sand, or ice in a corner, or; hidden danger (blind curves, over the crest of a hill, bambi in the ditch, etc). And even now, after 2 seasons, almost 40,000 kms without a scratch on the bike or me, and several advanced riding clinics, if any one of those 3 pops up I instantly go into newbie mode (as hard as I try not to). Something tells me I may never get over it. So I compensate. I avoid groups with more than a couple of riders I don't know, or I leave hundreds of feet between myself and the rider I'm following. I never intentionally outrun my sight line, and I take corners with scattered debri at a sedate pace.
Maybe that makes me a puss, maybe it doesn't, but I'm still riding (and still having fun) and that's really all that matters to me.
Chris
p.s. I've read the advice "ride your own ride" hundreds of times in this forum, and that applies in spades here. Only you know when it's right for you to get back on.