This is always a hard one for me as I worked for the Calgary Humane Society for 4.5 years and met some of the worst pet owners in this city. This includes people who felt that dogs were disposable and not worthy of the basic necessities of life. The Pet Parents I meet are polar opposites.
Let's break it down a bit... why do you feel guilty?
1. You feel as though your dog isn't getting enough exercise.
This may or may not be true depending on the family I see and why the dog might not be getting exercise. If your dog is aggressive and a danger to the public then yes exercise is most likely something you put off or are very nervous about. If your dog gets too tired after a 20 minute walk this is also a reason people feel guilty. So let's break it down a bit... depending on the breed and age of your dog you may be over or under exercising.
Puppies (8 to 16 weeks) are often not great candidates for long walks. I find 15 minutes for most puppies is more than enough. You can do 2-3 of these shorts walks in a day. And possibly for your puppy 5 minutes at a time is enough. They are often quite happy to sit outside with you and explore the world around them. You can try taking them new places and letting them sniff and explore. This will allow their brains to process new eliminates of the environment and for them to be socialized in a variety of places.
Seniors are also often not great candidates for long walks but it does depend on the individual dog. Senior dogs may get sore from walking on pavement too. Try a park where you can allow your dog to walk on a long line at a slow pace on grass. Tailor your walk duration so that your dog does not get sore.
High Energy Breeds - so let's face it I could walk my German Shorthaired Pointer for 4 hours straight on leash and he wouldn't be tired (not even a little bit). His exercise needs to be off leash running (Quadding seems to work well), hiking off leash so he can explore and smell or physical activity found in dog sports like agility or tracking. If you own a high energy working breed then you need to be participating in a diverse amount of activities that work the brain and the body.
2. You work a long day (8 to 10 hours away from the home).
This is another concern but a reality for most pet parents. You have to work to pay the bills so you and your dog can have a roof over your head and food on your plate. This is more than many dogs around the world have. You can only do your best. Great options for friendly, well adjusted dogs can be dog daycare 1-2 times per week or a dog walker everyday or every other day. If you can't afford that then try a walk in the morning where your dog can do lots of sniffing, followed up by interactive feeding with a Kong, Treat Stix or Tricky Treat Ball and another walk or dog sport activity once you're home from work. Most dogs (especially those in dog sports) need around 19 hours of sleep per day. Does that make you feel less guilty???
3. A few times a week you like to go out with friends, play human sports or eat dinner out.
This is true for most pet owners and can be a real stress. Your dog is a part of your life but for most of us your dog isn't your whole life. If you want to do activities in the evening try to mix it up so your dog has had a great day the day before. This is another time when a dog walker, dog daycare or family friend can help you out. Try not to feel guilty and occasionally even my dogs have to put up with a boring day when I have other stuff on the go. This is usually when they'll get a nice awesome bone to snack on.