We've been in a bull run but investing in crypto isn't that easy,it can be damn stressful..most of us are usually obsessed I.e, checking our crypto wallets every half an hour if not minutes
Few ways to remove your emotion from investment
*Never invest into Bitcoin more than you can afford to lose
*Don't borrow to buy btc
*Vary from btc into alt coins
*Buy and trade btc in a trusted and legit platform i.e, binance..

I disagree with your third point, altcoins will make your life way more stressful than if you just invested in bitcoin, with bitcoin you do not have to worry about having to go through thousands of coins just to find one that is worth something now and that will be worth something in a few years, bitcoin is the best coin in the market by far and you know that even if the price can go down from time to time it is still going to exist, have value and if given enough time it will give you profits.