Good on anyone that gives a hike a crack. I'll try to limit my post!
I'd suggest the Viewranger app to try and locate decent walks in your area. For Scotland the WalkHighlands website is excellent at flagging up decent walks and issues that might be out of your comfort zone.
Discover Scotland, one step at a time with Walkhighlands. The ultimate website for walking and hiking in Scotland, with thousands of free detailed descriptions of walks, places to stay, GPS waypoints, and proper maps.
If you have a bit more confidence, then buying an Ordinance Survey map of your surrounding area and taking a punt on routes that look interesting (e.g. varied scenery, or a walk into remote valley) can be enjoyable. The majority of my favourite walks are ones I've worked out for myself and that has the added bonus that they are quieter routes because people don't know them.
Also, going up and down mountains is hard on your body. I used to do a lot of that but honestly find views from valleys looking up at mountains just as impressive as views from up a mountain. Plus it's a lot less physical strain but will still have almost all the physical and mental health benefits. Hiking doesn't have to be about nearly killing yourself and if you've kids it can put them off walking forever if you start with something too ambitious.
Also, looking at weather forecasts (I suggest met office website) massively improves enjoyment. Why drive to a walk where there is a chance of rain when in the other direction there might be sunny spells?
If doing mountains is something you want to do then you can save yourself pain by doing exercises at home to build up muscles around the knees (lunges while holding weights gives me muscles that help me both with ascending and descending). Packing a basic knee support can also be a good idea (I often have one around my shin so that I can slip it up over the knee easily enough if I got to some testing ground or start to get a twinge).
And finally, if you've a dog keep it on a lead where there is any sign of livestock and consider avoiding cattle (which should be treated with respect and whose body language should be observed).
Apologies if I'm telling folk how to suck eggs. But yeah, walking is the business and everyone should try it at least five times in their life before giving up on it as 'not their thing'. Even at the smallest level, getting out for a daily lunchtime 10mins stride can be the key to keeping your sanity in a crap job.