While I love to travel and attend conferences and network, there is always the return to my regular job that I must face. Don't get me wrong, I enjoy what I do, but after a week of being gone it's often hard to come back. Not only are you back in your routine, which is always nice to get a break from, but you have to face the mounds of work that multiplied like bunny rabbits in your absence. Wading through the papers left for you, the email, and the phone messages seems to take an eternity. Then there is just getting caught up in general on all the work you would have been doing had you been in the office. And don't even mention unpacking.
I do make efforts to minimize this effect - halting listserv email, changing my voice mail greeting to redirect persons needing immediate assistance, and doing as much as I can while traveling to keep up - such as checking email and checking in periodically with the home front to put out fires that have cropped up so that they aren't awaiting me upon my return.
Still, the advantages of professional travel and involvement far outweigh these inconveniences. Growing always involves a few pains.