Exercise is one of the things I look forward to as part of my day. It improves the health of my body of course, but I also savour the effect it has on my mind - improving clarity, lifting mood and balancing out emotions. During my life I've certainly used exercise to work out some frustrations, think through difficult situations and push forward during heartache.
My personal routine has changed a lot over the recent years; previously I would mostly run, then attend the gym and lately I like to mix in both high intensity cardio with weights mostly all at home. Completing the work out at home allows me to involve/supervise my children and cuts out the travel time to and from the gym.
I find changing the routine and having a goal to work towards are often good motivators when motivation is a challenge (e.g. on cold winter mornings!) Having a variety of routines to call upon depending on how my schedule gets changed is also useful. Examples of goals I've previously used have been half-marathons, obstacle course races and stair climb challenges.
Current exercise recommendations (as per Australian Department of Health and Aging and Heart Research Australia) for most adults are between 1.5 - 2.5 hrs a week of high intensity activity (hard running, playing a basketball game etc) or 2.5 - 5 hrs of moderate intensity activity (brisk walking)
Note that these are guidelines, and getting a little more in (within reason) is usually a good idea. With my patients I will encourage them to make it a priority to get 20-30min most days and to find something they really enjoy doing - run, cycle, swim, gym class - there are many options. For those who are more social, playing a team sport or enlisting a friend to go to the gym with and keep you accountable is also a good extrinsic motivator - but remember that intrinsic motivation is usually more effective in building good discipline and habits. Those of you who feel you don't have enough time, remember regular physical activity is also shown to improve productivity (work, family time, sleep) so its probably more something you can't afford not to do rather than the other way around.