I mostly don't do gifts anymore. I've never done wedding shower/baby showers - I just don't go. I didn't do a wedding shower, and I had my kid when I was overseas living in isolation so I didn't get any of the baby things from others, and maybe because of that I feel less obligated to buy things for other people's babies. That, and most of the crap people buy new for showers could just be picked up free from craigslist. Luckily I hate all the crap that goes with those parties, so I can just decline the invite and not feel like a mooch eating their party food.
Attending weddings - I will give cash, not a gift, knowing that it will help defray the cost of the wedding and my meal there.
Anyone coming to the door to sell stuff - I just don't answer it. Problem solved. If I am not expecting someone and there's no delivery truck in my driveway, I know it's politicians, sales, or religion come to call. I don't feel any more obligated to open the door as I would to answer the phone if caller ID shows it's spam. Once or twice I had an urgent sounding knock on the door. I opened an upstairs window, called down and checked that the person was okay. I don't want someone bleeding to death on my porch while I refuse to help. But pretty much nobody's going to try a sales pitch when they have to twist their neck up uncomfortably and shout at me, so those talks are short and sweet.
Office charity stuff - no. A simple no thanks when asked to donate is all that's needed. If pressed - we do charity donations through payroll deduction, so we can plan our budget for it at the start of the year.
When I do get gifts, it's because something strikes me as a thing just right for a particular person, and I don't necessarily wait for a holiday. When my dad - a musician - was laid up in the hospital a few years ago from a heart attack, I got him his first ipod, preloaded with music, so he'd have something to help pass the time. Last year for christmas I got him an amazon prime membership and a firestick so that he could watch the series "treme" (music based - and actually he knew some of the musicians with cameos, so it was perfect!). Both those gifts were things, but they were experience based. Other years, I don't get them anything, or sometimes I might make up a spice blend I like and edible things from ethnic stores around here that they don't have access to.