Bitterness and resentment can arrive if you don't spend some time thinking about what brings you pleasure, and planning those pleasurable times.
In some places, the search for pleasure is looked down upon--perhaps it is Puritan roots or an over-cautious nature that creates this sentiment, but on the contrary to know your pleasures and build time for that makes for a better lie. Knowing your pleasures, also creates good energy, the kind of energy that lets you power through the tough work so you have time and capacity for those pleasures.
Too often, when we're too busy, we let others dictate our pleasures. We may be drawn by popular notions of pleasure or advertisements that convince us of what our pleasures are. To avoid these false pleasures, you need to make time to think about what you really enjoy. For me, one great pleasure is spending time with my husband and children--I truly love to share a meal or embark on an adventure with my husband and children. Another great pleasure for me is travel--I love every aspect of travel from planning the trip to going on the adventure and then looking back at the good times. Identifying your pleasures and the pleasures of those you love is a great way to begin creating terrific daily and weekly routines as well as yearly traditions.
Looking forward to these pleasures also energizes you for the laborious tasks and efforts that lead to these favored events. It's easier to save money, complete onerous jobs, and be patient if you know that a favored event is coming up.
To consider your pleasures as a way to elevate energy is a lot more enjoyable than chastising yourself about the needed tasks and events you've been neglecting or dreading. Onward.